I’m surprised I had to go this far to find immich. I 100% recommend it, and yes it’s selfhosting if you run it yourself. Still selfhosted even if you use a VPS as long as you control and administer it.
For hardware, I actually recommend against raspberry pis these days. You can get a cheap mini PC that’s much more performant and better supported for the same price as a pi plus the accessories (SD card, case, power supply, etc). Use Debian or Ubuntu as host and follow the guide on the github for installation.
I love this show and can confirm, they are the worst