Before I left Reddit, I used a plugin through the api to replace all of my comments with random gibberish and then delete them. Part of this was because (mandatory) fuck spez. But more importantly, it was to protect the anonymity of my account. After years of posting, there is likely enough personal information shared to potentially connect my Reddit habits to my online identity. I wasn’t planning on using Reddit again in the future on that account, but I left it open in order to maintain some security control over the account. I’m not really sure what to do at this point because I still consider it a security vector that’s a bit concerning. There’s no way I can manually edit and delete all of my content with the snail’s-pace reddit UI, and I have no ability to assure that my content will remain unavailable or at least not publicly displayed.
I had a similar issue. I had probably two million comment karma spread across about a dozen accounts. My first account was quickly auto-banned from several subreddits as soon as I started editing old comments. Those pro-spez mods had seen what people were doing during the exodus, and set the automod to ban those who tried.
Then I did the same with my second, third, fourth, etc accounts. All of those were immediately site banned for ban evasion, because I was interacting with subs my first account had just been banned in. So none of the edits on those later accounts were pushed through.
Reddit later un-banned those accounts, and all of my old comments were visible again. Likely to make the old comments show up.