Some minor notes to add:

Pi 5 is just released, highly recommend it as it's much more powerful (2-3x faster than Pi 4)

Pi 4 mentioned in our build is great for a Bitcoin Node, a Lightning Node (with 10ish tops channels) and not really much more. If you want to have a much more serious Lightning Node on it that routes a lot of other peoples payments then it's better to just go a with a few years old mini PC with like, Core i5, 16 GB RAM, SSD etc. This is obviously more expensive, but it'll be able to have essentially unlimited channels and do a number of other things. When routing payments speed, uptime etc are all part of the routing metrics, so a slow Umbrel over Tor with a handful of channels doesn't usually work well.

Speaking of doing other things, if you want it to store / host / sync data like photos, files etc don't use Umbrel. Just buy/use a proper NAS like Synology or QNAP. Yes they're more expensive (~$1,000+ vs ~$300) but that's a LOT cheaper than losing all your data!