The beginning of the end for Reddit was when they started changing the rules specifically to target certain subreddits.

When the mods and users dutifully complied with new rules, the admins got frustrated and began curating r/all and r/popular to prevent posts from those subs from appearing.

When that didn’t work, Reddit would then quarantine or ban subreddits based on obvious and organized spam of against-TOS material and subsequent mass reporting of that material by the same individuals.

Once those purges were done they started the enshittification that continues in high-gear to this day.