I first joined Reddit in 2007 when it was a genuinely friendly and informative place. The first big change came with the Digg exodus which brought mainstream meme culture. I think at that point, Conde Nast starting putting serious pressure onto management for Reddit to become more of a social network. This then led to the broken UI changes which, as you say, brought the wider bell-curve of humanity with it.
The problem is that Reddit simply didn't have the security controls/moderation in place for that type of activity. By 2016, Reddit was being widely manipulated by outside sources -- Large corporations were hiring troll-farms to shill their products; Nation-state actors were doing the same; political activists were trolling/abusing Reddit's systems in any way they could -- doxxing, death threats, extreme trolling...
And the friendliness and trust were gone forever. And instead of having discussions, it's now just everyone shouting over each other.
Now the management just want to cash out and using Reddit is now like writing a college essay while sitting in a McDonalds basmement eating a stale three-hour old Big Mac.
I'm really sorry to hear that they did this to you. I went through something similar, but only as a poster.
There was a really famous Usenet poster called Humdog who, back in 1994, wrote a brilliant essay called Pandora's Vox: On Community in Cyberspace. It talks of how cyberspace, instead of doing away with hierarchy and creating equality, actually commodifies its users and transfers power to large corporations.
You can read it all here:
https://archive.org/details/pandoras-vox-on-community-in-cyberspace-by-humdog-1994
https://en.wikipedia.org/wiki/Carmen\_Hermosillo
It really does show that none of this is new. It's what the internet really always has been.