Yeah, this bothers me a lot with mine too (an RM2). I can't believe how heavily I have to press to get full line width on many tools, it's harder than I press when I use an eraser on a stubborn mark in real life.
Responsiveness wise... the latency on common actions has increased incredibly in the past couple of years. Not pen drawing, that's still excellent, but general UI navigation and recognizing taps and long presses and whatnot have really gotten bad. At this point I've got it rolled back to 2.x almost all the time, which is also a whole lot more moddable than 3.x. I like many of the UI changes and additions in 3 (except infinitely vertically scrollable stuff, that keeps screwing up and interpreting taps and swipes as vertical scrolls when there's absolutely no additional content to show, so it just stops responding for a second while it scrolls three pixels down, and I would be thrilled if I could disable it completely), but not at the cost of responsiveness.
I currently use RCU (Remarkable Connection Utility) to extract my highlights: https://www.davisr.me/projects/rcu/