My collection has always been a big source of shame for me, to the point that I never tell anyone about it and have only one friend who has actually been inside my home.
I feel you on that one. I've certainly gotten better over the years, but I understand the shame aspect. It's silly too, because I'm always the person who's telling others to be proud of who they are and what they like, and to not care what others think or say, but following my own advice? So difficult!
Ultimately, I think it's a societal thing. We're taught what an adult ought to be from a young age- responsible, tough, future-minded, etc. Hope I'm not opening a can of worms by saying this, but it's a similar argument to the whole "masculinity" thing. My dad drilled it into me at a young age what a man is supposed to be, all of which was rather idealistic and stuck in the past (and ultimately quite misogynistic). It's taken me ages to unlearn all that, to be in touch with my emotions and not shove them down for the sake of appearing more "masculine".
I think it's the same with collecting to an extent. For years (and even still) nerds were the butt of the joke. A grown man collecting action figures was seen as a silly thing, and all nerds were squeaky-voiced, inhaler puffing, socially awkward, pimply man-children living in their parent's basement and can't even date, let alone supply for a family. Are there nerds like that? Of course- all stereotypes come from somewhere. Didn't even matter your sexuality- gay or straight- being a nerd was cringey. The idea of it being "cool" to be nerdy or into comics or figures or whatever is still a relatively new thing, I'd argue since the Nolan films and MCU became a thing. My sense of pride, I never wanted to be associated with that, because it went against what I was taught to be. I could also note that the current day idea of a stereotypical nerd has also evolved to include the toxic collectors- the ones who either knock others out of the way to get something, buy out a store's entire stock of something, or are overly gatekeep-y or rude to others, and that's another thing I don't want to be associated with.
Collecting was kind of my secret shame for a while. Any time I brought a friend or date over (which wasn't often- I'm definitely someone who prefers to keep my social circle small), I was always filled with such anxiety at what they'd think. And sure, sometimes the reaction wasn't what I hoped for, but it was never bad. Some momentary surprise, or being caught off guard, but it quickly turned to admiration, and, like others have said, they almost always found something that reminded them of their childhood, and it helped us bond. I'm so lucky that my current significant other is super nerdy as well and actively supports my collection. We've been together about 7.5 years, and every time they come over, they still marvel at the collection and whatever new acquisitions I got.
Do I still have anxiety? Sure. Every now and then, my landlord comes over, and he's definitely a guy who doesn't "get" it. Bless him, he always tries to use choice, non-offensive terms (he loves to say "avid collector" like he isn't sure it's a slur or not). There's been a few times over the years of me living here where, after a visit, I'll get an email from him about having too much stuff and how I'm not tidy with it (I can be a bit cluttered, as anyone can, but having lived with a mom with OCD and ADHD, I know how to clean a space

). It's mostly dust that I need to work on, and that's more out of anxiety of having to take everything off the shelf than anything. His comments used to bug me, and they still annoy me, but I'm realizing more and more what a small deal it is. It may sting in the moment, but ultimately, it's one person's opinion over everyone else's, and everyone else I know loves my stuff.
I still find myself feeling reluctant to share my stuff with the world. I really want to be able to talk about new toys and things, or share photos of what I've gotten, but something still stops me. I don't know- maybe I want my friends and family to think I'm more financially responsible than I am, or to not get the wrong idea about me or my priorities. Still figuring that one out. But I'm making strides- I started my own YouTube channel and separate social media profile to focus solely on collectibles and such (and of course now I worry that all that stuff is or isn't up to snuff, but I digress). I'm sure I'm enjoying the anonymity of it, but it really is helpful to see how many other like-minded people there are, and to put more pride behind my hobby.
A lot of the progress has come down to me getting on the proper meds for all my mental health issues, and that's given me a lot of clarity, with both the embarrassment of things, and even the reason why I collect in the first place. It's helped me take stock (literally and figuratively) of what I have and which of it I need and which of it I don't. And of course with the world being what it is, these little bits of joy, and reminders to not only be joyful, but to not lose sight of the kid in me, and all the wonder and excitement that brings with it- are as important as ever.
I wish you peace of mind, my friend. If it's any consolation, I'm sure your collection is freakin' bangin'.