OpenReplay and Posthog both have session recording for JS apps. It's been really insightful (and often painful) watching our customers use/struggle with our software.

There's others but those two are open source if you're concerned about user privacy.

Posthog's site seems to be down, but thanks for posting these. I tried to pitch my company on Fullstory or Hotjar, but failed for reasons these options (which I did not find in my research, somehow) might address.

(Ironically it might be an ad blocker in your browser causing this!)

An alternative to traditional usability testing: Drunk User Testing! Your testers will be a little dumber and a lot more honest. :)

https://uxpamagazine.org/boozeability/

Read the entire document. There's a big section on research.

I did read the document, it talks about user interviews, surveys, testing solutions, etc... But never once the actual act of the designers sitting next to users and just observing what happens.