My reddit use and dropped dramatically with the death of third party clients, but this I think will push me off entirely. That just actively encourages reposting old threads and their comments wholesale.
Many years ago I made the laziest shitposting bot for 4chan ever, called trolldozer. which did almost exactly this, simple keyword matching and some homegrown weights assigned to a couple dozen known sequences. the bot just kept a roling snapshot window of posts made between 150-190 hours before the current time, found the oldest one that was most similar to a sequence of popular keywords in a given thread, and reposted to the end of iit but with no image link. Of course being anonymous this worked pretty well even if it got saged frequently, presumably when someone spotted their own post being reposted.