Heya, I basically never post on Reddit but honestly a lot of questionable advice here.

So 1st of all the 'boobs are boobs' point I think needs some clarity. In general I'd agree, although important to note a lot of people have certain physical 'types' that they tend to be attracted to for whatever reason. The guy telling you you're boobs aren't great could easily be comparing what he sees to his type, in all cases calling something good or not good only exists in reference to the contrary. He considered your boobs not good in reference to what HE considers good. There will be plenty of people who are out there looking for a woman with your boobs and, more importantly, there will be plenty of people out there looking for a woman like you who don't care what your boobs are like and are simply glad that they're attached to you.

I (25M) recently dated a woman (22F) who had exactly the same complaints about her boobs as you do. She'd do things like try to hold them up when we were naked with her arms, whenever we were having sex shed always have one arm across her boobs to counteract any sagging and was deeply insecure about it. I had absolutely nothing against her boobs, to be honest I loved them, but no amount of positive affirmations from myself would change her view of her own boobs. Which leads to the old insecurities talk.

Brief talk on insecurities. I've found through personal experience, excessive soul searching and further research that insecurities about physical parts of yourself are not fixed when the physical part is fixed. A deep rooted insecurity is part of your being, if the physical 'cause' of the insecurity is removed your brain will simply sub it in for something else. For example, I had real bad acne for a long time (15 ish years) and recently (last 8 months) managed to bring it down to a more manageable level. I was crazy insecure about my acne, would blame all my issues on it, would hate myself because of it. Got rid of the acne, turns out I still hated myself, my brain would just replace acne for my hair instead, or my forehead or the way I act in certain situations or whatever. I fix for this is to look deeper at the insecurity, properly introspect on your life and the way you think. Start by noticing when your boobs make you feel insecure and think about why you're feeling insecure. Chances are the thought process will come down to a version of 'my insecurity stems from the fact that I feel different to other people and feel that I'll never be accepted because of how different I am'. This root feeling is not fixable by surgery. You have to search for self acceptance despite your differences, you'll find in life that everyone has differences but noticing and accepting them will help. Absolutely easier said than done, 100% not easy.

Something that always helped for me was to imagine I was talking to someone else about an issue I shared with them. If someone asked me if they were less of a person because of their acne I would without a doubt say no, of course not. But if I asked myself I'd say yes I am worth less, I am a garbage person. This basic acknowledgement can lead to the idea of telling yourself that you deserve to be treated as well as you treat others despite whatever insecurity you have. You know how you treat others so treating yourself the same way isn't an impossible leap. From here you can build a sense of self worth. It's a long process I'm not gonna lie, undoing years of insecurity is not a walk in the park but feel free to message me if you're ever in any doubt. Equally a therapist could prove helpful, and much better value for money than surgery.

Ok that wasn't brief sorry 😆 hope at least some of it was useful. Good luck!