I turned off "Preload Images" and my feed hasn't hung since. There is still a tiny bit of wait time while the next group of posts gets cached in the feed (maybe < 1 second) and this is usually when post pre-loading would fail and hang the feed completely.

If for whatever reason, if an image can't be preloaded it'll hang the feed? Maybe if a post gets deleted on one instance and, because fediverse, it may still be listed by my home instance? A failed cross-instance image load does sound like an interesting theory for root cause.