My first node was an Umbrel installed on a Ubuntu laptop and it felt VERY unstable.
After just one week, it experienced a catastrophic crash that I was not able to recover from (I'm no expert and that's probably the reason why I couldn't recover it).
I've been using a Start9 Server for the past two months or so and thankfully never experienced any downtime. My paetners' RaspiBlitz goes down once every two weeks or so.