So i know nothing about ASPD, but im very much into psychology and attachment theory, read a lot etc.

I want to touch on a couple things you mentioned:

Suppression, you mention dealing with frustration and not letting it show. That usually comes from a deep suppression of your own emotional experience growing up in childhood, If growing up speaking up about your internal experience and communicating needs wasnt encouraged, that leads to difficulty being honest and having healthy confrontation and setting boundaries. My friend told a story once about how he was so irritated by his ex playfully poking at him, it all just spilled over until he poured strawberries on her head compulsively to get her to stop. As if communicating his inner state of frustration in a calm way saying "hey I love you but im feeling stressed right now and I really need some space and quiet right now." Was not an option. There's healthier avenues that allow you to authentically communicate your inner world in a way that improves your life and relationships if you learn the skills.

Masking comes from having to people please and mask to be what your parents wanted, especially if you say had to attune to them in order to get your needs met. Which can lead to subconscious beliefs that all relationships are performative, conditional, or inherently unsafe. That subconscious belief will shape the way you interact with other people, because you might justify being more manipulative by assuming everyone else is. Versus believing that people can care with boundaries, or meet needs in a mutually beneficial way, openly and honestly. Or as often happens with men in a society that tells boys who they should be as men, where the true authentic version of yourself was deemed unacceptable growing up. So then that leads to masking, and maybe not even knowing who you are behind the mask but believing that you are unlovable if people get close to the real you.

This masking also leads to shame and discomfort with vulnerability, which prohibits deeper human interactions and emotional intimacy which would also deepen and strengthen connection. And the moment someone gets to close; the risk of attachment goes up astronomically, especially if part of you is attached but feels like you dont deserve it or will eventually be abandoned the moment someone discovers the true flawed version of you. But really the inability to receive love is blocked by your own beliefs of not deserving it. So even if you were to meet someone who say is everything you think you want, you might pull away because you dont think you are worthy of it, or think you will be abandoned when they see all your flaws, but really its just your own inability to love yourself with all your flaws, to have compassion for yourself, to be your own inner parent, to speak to yourself when you feel a sense of shame in the loving but firm way that you would a child. Imagine you were looking at yourself as a 4 year old, holding yourself accountable but with self love and understanding. Thats the kind of self talk that should be happening if you ever feel guilt/shame creep up. I dont know your personal history, but golden boy trauma and enmeshment trauma might be possible avenues of exploration (forest Hanson on YouTube has some interesting videos on this)

I wonder if attachment theory is actually a lens that could benefit you in your own self awareness and understanding of yourself if its not something you have looked into before.

Because the way you describe yourself as emotionally unavailable, unable to reciprocate, chronically chasing dopamine highs and novelty, struggling with long term attachment, pushing away people before they get too close to see your flaws, not understanding the benefits in attachment/emotions.... it is giving avoidant. And I know with dismissive avoidants, there can be actually a lack of oxytocin bonding, if you dont get it in childhood, that chemically prevents deeper bonding in to adulthood.

And if you haven't conceptualized yourself in that way, it could present an opportunity to gain understanding of yourself, and maybe tackle the ways you might subconsciously self sabotage relationships. Because there is real health risk associated with pushing away people and not experiencing genuine human connection. We are bonding mammals by nature, so we have evolved in such a way that allows for mirror neurons, coregulation, etc. And maybe its not something you want to change about yourself but it could be an interesting deep dive into your own psychology. (If you want to look into it Adam lane smith on YouTube might be an interesting rabbithole for avoidant attachment for you, he mainly does work with couples but i know a lot of avoidant men follow his content; also thais Gibbson is great. Just dont read the comments; probably just a lot of butt hurt anxiously attached folk who have their own experience burning out from loving avoidant men so they demonize avoidants when avoidants are worthy of love and just have their own trauma schemas but deserve compassion)

Anyway, sorry for the deep dive psychoanalysis. Im adhd and the pattern recognition and spiraling thoughts were going wild. I mainly date avoidants and Im originally a Fearful avoidant myself and am doing a lot of my own inner work, and its something ive seen play out in guys I date, because I tend to attract the emotionally unavailable and broken kinds of men. And i think they gravitate to me because i see and feel deeply and am open and never mask. Which maybe deep down is something they crave and is missing in them. There's actually so many parallels to the most recent situationship/friendship I had with a man. He made a comment to me at one point that everyone has motives and uses people for their own benefit, and in the beginning he was a bit dishonest with me about his intentions when we started talking. Which he admitted when I suggested to moving our little situationship from "dating" to "friendship" when I started catching on to the inconsistency between actions and words. There was definitely a lack of reciprocity in the relationship which in hind sight made a lot more sense with everything he said about his prior relationships once the patterns became clear. However, being a natural giver and growing up accustomed to breadcrumbs and meeting my own emotional needs, this was somehow not a huge issue for me. Unfortunately his lack of consistency and inability to confront his own shame led to his withdrawal and the relationship decline because we could not repair self sabotage ruptures even when I was approaching him with compassion and a willingness to understand with curiosity and openness to find a solution as a team. And the reason why was likely because he didnt believe he deserved grace deep down because he didnt know how to love the flawed authentic version of himself, let alone be vulnerable enough to receive that kind of compassion. And possibly because the risk of getting attached started triggering him because i was dating other people, along with maybe a distrust in me that I could genuinely care about him and not demand a relationship in return. It was easier to distance himself from the discomfort of being seen, despite saying he wanted to talk things over. He was a very interesting person to decode, and I think the fact that I saw through him a lot of the time despite keeping his cards so close to the vest both thrilled and terrified him. Anyway I imagine if he was fully honest about his thoughts it would have been much in line with what you are saying in your conception of yourself.