You have a Thinkpad? As far as i have heard their linux compatibility is fairly good. An yes, ubuntu won’t have more problems than windows with low power devices. My old 4GB ram, 1.4GHz 4 core laptop ran linux mint fine.

Ps: linux mint is a ubuntu fork, and has a desktop interface that looks a lot like windows (example: in the bottom left there is the linux mint logo that you can click to open the start menu like on win 7).

Most apps worked out of the box. It feels like gimp is a little bit (very tiny) slower at starting. For OpenTTD i had to manually add the x11 access in flatseal. And for osu! it is the only way i can play the current version, and that just works.