Very nice! I'm starting to believe the no-JS life may end up being the only answer to the enshittification of the mobile web. One of the reasons I built my own iOS browser was to have a "disable JS" button readily available, so I fully support you!
Great question, thanks! I've got 200 tabs currently open on my phone :)
Memory wise, at most 8 tabs can be kept alive in the background. Then based on the phone thermal state, that number decreases to 4, 2, and then 1.
Additionally, turning on Low Power Mode suspends all background tabs immediately, which is also convenient. I should probably document that behavior somewhere actually :)