That's actually possible to do, in a way, if I'm understanding how the new system works.
In the old system, you used to be able to look back at each person's posts and threads (through separate links) 20 pages back, and even more so through old likes. I could find my own posts and threads dating back to around 2010 (I've been here since 2009.)
The new system only seems to record a user's history 10 pages back, and that includes both their posts and threads. All you have to do is keep posting, and it will push all of your old posts out of the system. For example, now I can only find my posts dating back to around 2016. So, every current post you make will push an old one out of the system.
Likes and reactions might be a different story though. I haven't checked how many pages of likes are recorded for each user, but it might take a little longer to move those posts out and get them to disappear.