I have been run Docker container in both LXC and VM for a long time without issues or meaningful performance penalties. So I run important single docker containers on top of LXC and everything else in Dockge / Portainer VMs.

Eaton are probably the best out there. In my experience battery last between 3 and 4 years.

An new AMD Laptop APU will outperform Intel in every metric. I can only recommend T14 & T14S but any other Thinkpad will be ok.