Well, let me put it this way. I would donate $250 to fix it. I think that's how much working support for touch, trackpad, and pen input would be worth it to me.
I would donate $0 for a stranger on the internet to try to fix it themselves.
I would donate $0 and advise others not to donate with an approach where there isn't even a developer driving this themselves ("Give us money, and we'll hire someone to fix it" approach), especially with the claimed problem, solution, and approaches.
With open source, it's easy to find people to do the fun, modular bits (acceleration curves, palm rejection, etc.). It's hard to find people to do the plumbing and the not-fun bits. If OP were to create a pipeline which:
* Supported the broad range of trackpads, tablets, styluses, etc. on the market
* Did this with clean abstractions and modular drivers (NOT wrappers around wrappers around wrappers of what other people have written, but the painful work of refactoring other people's code)
* Integrated with the desktop properly, potentially extending existing standards if necessary (NOT tried to replace the desktop with yet another standard no one supports)
* Handled the odd-ball cases (a touchscreen, a drawing tablet, a drawing display, AND a plain old monitor are plugged into a box. What happens?)
* Provided clean, simple, documented, pluggable APIs where people could tinker around with the fun stuff (anyone can make a new algorithm in Python and see it work in 5 minutes)
That would solve the problem.
For reference, their approach: "(1) evaluate which multi-touch features can be implemented with the least work 2) start to quantify the current nature of palm detection 3) measure how the acceleration curve of Linux touchpad compares to that of macOS. I have some ideas on how we might calibrate the acceleration curve to better match macOS, but it would be handy if anyone else has bright ideas on how they would attempt to quantify the touchpad acceleration curve on macOS (such that we can seek to match it here)."
I could be wrong about all of this, but that's what it would take for ME to donate. I guess the other approach is to accomplish something yourself and establish a track record. I WILL instead donate to DIGImend, where a lone developer seems to heroically be successfully bringing tablet support to Linux. That's an example of a track record.
https://www.patreon.com/bePatron?c=930980
https://liberapay.com/spbnick/donate
https://www.buymeacoffee.com/spbnick
I'm sure this will go -5, since most critical posts do, but I find critical feedback to be more important than positivisty.
edit: Just donated to DIGImend.