The sub-world of modern standards is a frustrating and restrictive one. I bought a lovely wheelset with microspline, so I thought I would move to 12 speed. Which meant new mech. And new shifter. And then I found that also meant a new chainring. Ands that meant a new crank….argh….purchasing spIral…
Then…bought a 35 by 35 stem…argh…entering another compatibility vortex…..
Should have come here first
I went through all of this on my cargo bike. Was a 1x10 from the factory. Inferior drive-line kit which wore out prematurely IMO. Wasn't good enough to my simple life so why not complicate things and convert it to 1x12? Was just about to go through the mental anguish of building a Hope Pro 4 rear hub, microspline freehub, Hope E-Bike MTB rim, build the wheel, go through spacing and chain alignment issues...then I discovered from someone else on a different forum the 12-spd cassette made by SunRace. Fits directly onto a Shimano HG freehub with zero modifications. No chain alignment issues, no redishing the wheel. Less than 1/2 the price of a Shimano XTR 12-spd cassette.
Rather than build the Hope wheel w/microspline freehub + Shimano 12-spd cassette (was going to use SLX for price/longevity), rear derailleur, chain, shifter... all I had to do was buy the cassette, chain, derailleur and shifter with the new information.
I went with XTR SGS, XTR shifter, Sram X01 Eagle chain (dollars to donuts absolute best price for longevity for a 12-spd chain), SunRace MZ903 cassette.
Edit: For chainrings, maybe have a look at the brand Wolf Tooth.