I blocked some core jQuery files for the UA google lighthouse, I wonder if it actually works, or it just let me get a high score, essentially, google still thinks my score is low.
Google measures core web vitals via CrUX reports - https://developers.google.com/web/tools/chrome-user-experience-report/
The metrics are measured in real world when real visitors visit your web page.
These real world metrics aren't going to change by removing some jQuery libraries for lighthouse UA. Those core metrics are the ones that are going to increasingly play the part as ranking signals.
I believe you want to ultimately improve SE rankings by increasing page speed score. If that is the case, removing jQuery for specific user agents is not going to help.