Welcome popcanman! Everything you mentioned, those of us who have accepted our breasts have thought or gone through. I developed in puberty due to hormonal imbalance. After being picked on and bullied, like kids do, i fell into a depression about my body. I began overeating with the thought that I could "hide" my chest with fat. All it did was put my health at risk and I ultimately had to lose 100 lbs, which I later found out, fat creates more estrogen and so after losing the weight, I had actually gotten larger. I am now wearing a 36DDD/38DD bra, depending on the bra. I too looked at surgery and decided that it was not something I wanted to go through with the remote possibility my gynecomastia could return after surgery. I prefer underwire bras due to the support and containment they provide. I have been wearing bras everyday for several years now. There are others here who have been wearing bras a lot longer than I have. We all have our own distinct stories.
If you want to find out what might be your true size is, you will want to get six measurements and then there is a bra calculator called, A Bra That Fits. Plug those six measurements in and you can get a good starting point. The six measurements you will need are loose underbust, snug underbust, tight underbust, standing bust, leaning bust and then lying bust. Here is the URL for the calculator,
https://www.abrathatfits.org/calculator.php Don't be surprised with the number and letter(s) that come back. Cup size is a ratio of band size and to get the correct fit and to be comfortable (yes, bras can be comfortable to wear!) style of bra plays into it as well. I always thought I was a large B or small C. I could never comfortablely wear those cup sizes. They were too small, even though many "bra calculators" said that was my cup size. Imagine my surprise when a DD cup fit me perfectly! Problem was those calculators were basing it on two measurements, underbust and bust and that is one of the many reasons 80% of women wear the wrong size bra. It is usually the band is too large and the cups are too small and the band is riding up the back and the shoulders are taking the load of support, which is not how bras are designed. Reverse that (yes the cups letters get bigger) and support and comfort increase. Remember, the band is designed to take 80 to 90% of the support, not the straps so the band needs to be tight enough to anchor on the rib cage being horizontally to the floor when standing without moving around under normal movement of the body like raising the arms or twisting the torso. The straps are to give upward structure appearance and to keep the bra from moving down the body under normal wear and not support the breasts, particularly true with large breasts that can put a strain on the shoulders.
Many men who have gynecomastia usually have shallow breasts (meaning that most of the tissue is at and below the nipple, think in a tear drop shape) and wide set (meaning that you can put at least 3 fingers between the breasts when placed at the sternum) think with not much cleavage. This shape actually works in favor for men who wear bras since women are usually full or round in their breasts and their breasts sit closely together creating cleavage.
Clothing can be tricky. Until you find your size and what style bras work for you, not all will and that is true for women as well, it may be difficult to find something that works to start with. I personally have found wearing a women's layering tank under my shirts help smooth out the lumps and bumps and outlines a bra can give. Also, the women's layering tank has less bulk, is made for layering and is considerably cooler than a man's cotton tee shirt. Non-fitted button downs can work since they give some room in the chest, you just have to be careful that the waist doesn't get swallowed up. Also some non-fitted polo shirts will work. You may also want to consider non-fitted men's look women's button down tops. These will give room in the chest, but you will want to not get the ones with fitted waists. The buttons will button on the wrong side, but no one ever seems to notice! Pattern designs help confuse the eye as well. Stay away from horizontal lines. That will draw eyes to the chest since the lines will run along your shape and will define it in a way that is not flattering to men with breasts. Vertical lines should be avoided as well for the same reasons.
Clothing is something that is a trial and error kind of thing. It is never easy so take your time and while being critical with you look is important, don't be so critical that you miss options that would work. Most of us have found that people are too busy worried about their own lives to even notice you have breasts. For me, after I started wearing a bra and found what worked for me, i stopped trying to "hide" my chest and started to "camouflage" my chest, the number of "wondering" and "wandering" eyes dropped. That was a big surprise to me because in my mind I was "so sure" that everyone knew I was wearing a bra and could "see" my breasts. Truth was, I was the only one who knew and no one else cared.
Please know that this is a journey and it will take some time to completely get your mind around the fact that you are now wearing and depending on an article of clothing that society deems "inappropriate" for you to wear because you do not have the "correct plumbing" between your legs. It is really stupid. I have never considered myself trans anything. I am just a guy with unwanted boobs, and nothing more. Would I rather NOT have breasts? Yes. But the truth is I do have breasts and I also have "male plumbing". I think like a male. I act like a male (just ask my wife). I AM a male. But as another member of the community says, bras are for breasts not just for women. And this true. But I am also of the opinion, that if I have breasts, I want the same options women have when it comes for support, containment and comfort. Why should my genitals determine what level of comfort I get to enjoy? Just how I feel.
Good luck and welcome! We are here to help if we can, even if it is just a platform to bitch about our "assets".