I have a 2020 HT that has the same faucet and the same squeak. The whitish plastic/nylon piece is actually what locks the handle in place. Use a small diameter, non-pointed metal object (I use a nailset) to depress it and pull up on the handle. I have had to do this more than once. Once the handle releases pull out the nailset or whatever you are using to depress it and the handle will come off. Re-installing is easier, you simply push down on the handle and it will lock in.
I tried dielectric grease the first time, it worked for a while. The second time I sprayed some Boeshield T-9 on the valve assembly and it seems to last longer.
My expectations are that I will replace the entire faucet the next time it drives me insane, if it hasn't broken into pieces by then!
2020 Eagle HT 30.5 CKTS Modern Farmhouse (16" wheels, spring shackles set on lower hole of frame, SumoSprings TSS-107-40, standard kingpin, B&W Companion slider, TST-507 TPMS)
2019 F250 SRW SuperCab 4X4 SB 6.2 (10,000# GVW) 3.73 Axle 18" wheels