Despite OP's complaints (which are valid) I run Fedora on my Framework 13 (AMD) and I get 5 hours of work (10 ish Firefox tabs, multiple VS Code instances, terminals and Slack) without issue.

It's not 8-12, and the fans do kick up. The track pad is fine but not as nice as the one on the MacBook. But I prefer to run Linux so the tradeoff is worth it to me.