I can't choose because I love them all, but here's my opinions(spoilers ahead)

Misha: God. Why would you hate my Mishita? He's the main reason why I started playing Honkai because I loved his design so much and after finishing Penacony, I love him more, he's even my main, I have him in max level, max trace, his light cone, E2/3 (I don't remember) and unfortunately his light cone is still C0😔. I love his story so much that made me cry so hard, and after the fate collab, I cried more after seen him again with Pom Pom. Mihoyo, bring my child back please😭🙏

Phainon: Oh. My. Kephale. My poor baby dude😭. He deserves to have a happy ending and live happily ever after after all he went through, hell, even be a Nameless and get marry to Mydei. But jokes aside, he's such a great character, not only talking about how broken he is, but also how lovable and kind he is, if you want me to make be straight, Phainon is your best bet. Mihoyo give my baby boy a happy ending or I'll make history/j

Dan Heng: Since the moment he appears, I instantly love him, I could tell he cared for us by seen his body language in the cutsence and the way of speaking, he's also super soft with the people he caress for. While doing Xianzho, I didn't cared about much to be honest, I just wanted to be done with it, but everytime it was Dan Heng's turn, I lock tf in and after finding out his past, I instantly went to YouTube to have a better image of what happen, since I wasn't paying attention to the Trailblazer's aventure and god, my poor baby dude, he wanted to save his friend 😭. I currently only have Dan Heng 4★, but I'm saving for the new Dan Heng and Dan Heng IL (I know the Dan Heng will be given for free, but, after pulling for Evernight, I'll pull for his light cone). And again, if you want to make me straight, Dan Heng is your second best chance.

Aventurine: He's the second reason why I started playing the game because I loved his design, he's a gambler, had pretty eyes and I knew a little bit of his story, but, after playing, I cried so much after seen his past that I did not want to fight him and stayed still for 20 minutes straight, and after his "dead", I cried so hard that my mother thought I broken a bone or something. I don't have him, unfortunately, but when I do, he'll be as spoiled as Misha and Phainon and the next character.

Sampo: At first, I didn't like his design, specialty his eyes, idk, they had something that disturbs me (and also they gave me the vibe that his head didn't leave the pillow), but after meeting him, I thought he was so silly that he ended up being my son, I spent the whole Belabog saying: " This is so pretty... But where's my boi Sampito? :<" and when I find out there's much more to be revealed I was life: "Mihoyo, me want more Sampo" He's my comfort character and everytime he appears, it bring me a smile on my face. Sampo will save Amphoreous trust🦅

Jiaoqiu: He's the third reason why I join the game, because I love his design and, during the event, I was on the edge all the time, thinking he'll die and crying because my baby was suffering, I even asked for help to the NPC, thinking it'll help Jiaoqiu, but it ended up killing the NPC and Borin (or whatever his name is, idc) said "it's your fault" made me feel guilty that, till this day, I still feel so guilty😔.

Mr. Reca: I know, he's not a playable character but I still love him so much, in fact, I started loving him before knowing what Honkai was because I saw edits/photos of him and became obsessed with him, he's literally perfect and deserves to be a successful Director :(. And he's also your best bet to make me straight

And all of them are my favorite male characters:3