You can self host immich on a device as small as a raspberry pi. Waveshare sells a CM4 board + enclosure + power supply for $36. You can get a 1tb 2242 nvme ssd for $99. And you can get a 4gb CM4 + 32gb emmc from adafruit for $65 (currently out of stock there, but you can keep an eye on rpilocator. some capable boards are available in Germany, but they’re over $100). Not the cheapest setup, but if you’re worried about power draw, spinning hard drives, and portability, this would be a way to do it. You could also just host NextCloud on it, but it might be a bit slow.