Cool! I always recommend OsmAnd.
You can also install it directly on your machine: https://github.com/Flomp/wanderer/wiki/Installation#from-source
It’s just much more tedious imo.
You can use whatever device you prefer. In the end, you simply need a GPX file that you upload through the web UI or the API. I am planning to support other formats like KML soon, though.
System requirements should be quite low. On the first startup you will need ~1GB of RAM. After that, the whole stack sits at around 100MB on my machine.
I really love working with PocketBase. It gives you such a headstart, but also is highly customizable. It’s really the best of both worlds.