I'd say mint or debian, and NixOS is neat if you're willing to spend weeks on it. It allows you to make reproducible and declarative systems as well as declaring sets of packages for the current thing you have to do
javascript shouldve only been used for changine element state and sending requests. anything more major, like mic access or custom players, would be sandboxed wasm that asks for permissions
how much are old thinkpads nowadays? im thinking of switching to one, really looks like they can hold up for 5 more years at a reasonable price