Marlin 2.0.x.x firmware for K40, anybody using it?

I am currently using Marlin 2.0.9.1 custom complied with laser support for an SKR 1.4 turbo board. While it works, the performance is very poor. Raster engraving is only smooth at around 10mm/sec. Regular cutting moves are okay, but power is not adjusted with the move velocity which makes the beginning and end of cuts more burned.
The stock Nano board and K40 Whisperer seemed to do a better job.
Does anyone in the Lightburn community have a good experience with Marlin?

Thanks