Found this brilliant program called 'Lazy Nezumi' recently, more than just a tablet-pen stroke smoother, it also comes with a bunch of stuff I missed from the days I used to do traditional, including the ability to draw ruled lines and even perspective stuff without the tedium. As someone who does rely on doing lineart and inks, it's a definite purchase from me.
I only discovered this today, so I've barely scratched the surface so far. I'll let people know what I come up with using this tool-assist later on.
https://lazynezumi.com/home