After trying multiple libraries I always encountered errors, non working pins or performance issues. While digging through mbedOS documentation and related forums (thanks to user haplm) I've put togheter this, in order to process my 5 channel receiver data.
The implementation only uses mbedOS provided functions, is easy and blazing fast
You should not use this combined with the simplified Arduino "Serial" library, it creates timing conflicts and the proportional readings are innacurate. I don't actively use or develop for the RP2040, this was made only for evaluation purposes