I purchased 2 Pi4s to run various small self-host services on. I've lost two SD cards in the course of about 6 months, and I've generally had stability problems with both of them, the hangs seem mostly tied to SD card and USB controller issues from what I can tell. I think my highest uptime is about 4 weeks. I'm not sure if it's heat or power related, or just bad SD cards, or general instability of the 4.

Regardless, I'm done monkeying with Pi 4s, and I'm moving to cost comparable PC Thin Clients for my self-hosting needs.

Never had any issues with several Pi3s over the years. They just don't have the oomph anymore for my needs.