Wacom. The very, very best is a second hand Wacom Intuos 3, if you can get a few spare pens. That's before Wacome started adding all kinds of smart interpolation curves to the tablet hardware itself. My Intuos 3 is eleven years old and going strong. We got it back then: https://dot.kde.org/2007/11/16/art-tablets-krita

I’m curious: what do these smart interpolation curves do, and why do you consider them bad?

They change the inputs to the painting application in a way that the user cannot influence; the app no longer gets the raw hardware take, but something that's "improved" and "smoothed out". And that's limiting. We can do our own smoothing, thank you very much, and leave the amount to our user's discretion.