Hey! My home server is an HP T630 with a GX-420 GI as well, but only 4 GB of RAM. I upgraded from a Raspberry Pi 3 and it's been awesome. I'm currently running 18 Docker containers on it without issue. I use Jellyfin on my primary workstation that has my media instead if this server, but I run things like Paperless, Nextcloud, Vaultwarden, Gitea, Wallabag, Pi-hole, NocoDB, and many more. It's been great, I think thin clients are a great low-cost, low-power solution to x86 home servers.
I paid around $40 or $50 USD for mine, so $10 sounds great!
Let me know what questions you have. I can try throwing Jellyfin on it to see how it performs too.
If you decide to not got the YunoHost route, I like the way this guide did reverse proxies with Caddy: https://github.com/DoTheEvo/selfhosted-apps-docker.