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.

Ubuntu was great, until Unity debacle, when I switched to Mint DE. Few years later I returned to an Unity free Ubuntu just to be welcomed with snaps and Ubuntu pro.