Right. You can't anticipate how historical posts can affect you later, but are there strategies to limit this exposure?
I haven't done this (yet), but I know some people will create numerous profiles and limit certain topics/subreddits/lemmy communities to specific profiles. That way, if profile A never discusses work or family, but only gardening, there's almost no chance that someone targeting that profile could do much harm.
I guess, this would be the same as having multiple email addresses or alias/forwarding email addresses... to limit what information someone could possibly get from you, even if they had access to all email related to that single account.