Make sure none of the exceptions are ticked and the Minimum number of articles to keep per feed is also 25 or below. Then its up to the cron when that runs so you might have to manually purge it and optimise the database to see what it will actually keep.
I can’t say I have ever worried about it, been running FreshRSS for years and it seems to keep its database size in check fairly well and the defaults have worked fine for me and it rarely gets above 100MB. So I know it “loosely” works in that old articles are absolutely getting purged in time but have no idea how strictly it follows these rules.
Initially a lot of the AI was getting trained on lower class GPUs and none of these AI special cards/blades existed. The problem is that the problems are quite large and hence require a lot of VRAM to work on or you split it and pay enormous latency penalties going across the network. Putting it all into one giant package costs a lot more but it also performs a lot better, because AI is not an embarrassingly parallel problem that can be easily split across many GPUs without penalty. So the goal is often to reduce the number of GPUs you need to get a result quickly enough and it brings its own set of problems of power density in server racks.