As someone with TrueNAS SCALE and having been through the mess of TrueCharts, I'd go with Proxmox on the bare metal and have 1 VM for TrueNAS SCALE and another for docker-compose or whatever apps system you want. SCALE is fine as a NAS but the apps system is currently limited and about to completely change; it's just not mature not stable. If you already have a home server running the apps you want and you're only expecting this server to be a NAS, then go ahead with SCALE on bare metal.

Use acid. Vinegar (white, cider, balsamic, rice, etc.), citrus (lemon), or wine.

GOG for DRM-free, unless there is a benefit to Steam. For example, Spelunky gets a daily challenge only on Steam.