Still using my AOL email account from 1993. Glad that’s not going away (yet)
I lately put my first AOL email account into Apple Mail and it also still worked but it was empty. Not sure if I deleted it myself. I needed to do some recovery process a few years ago because my password only had 5 letters and there was no phone number or so.
I think there was a mail about a change a few weeks ago. I hope it's still there and I didn't need to accept any new TOS or something like that. It was in Tahoe before i downgraded. I could try it here again.
I might have an old Thunderbird backup somewhere with all my old accounts and mails, most accounts don't exist anymore. Not sure if it's still there.