As far as I can tell, the spacing on Shimano and SRAM 12-speed cassettes is the same, so you should be able to use a 12-speed Sunrace cassette on the HG freehub body that comes standard on the Kickr. Buying a Kickr XD freehub and a SRAM cassette would do the same, but at vast expense, even if you can find the parts.
The cross compatibility is a bit of a lottery, but all the bike/cassette combinations I’ve used on a Kickr have been fine to use with a slight tweak to the indexing. If you count the half turns you make on the adjuster, you can simply reverse once you put the wheel back in.
The other thing you could do if you have the time / space / spares / inclination is to put together a turbo ‘bike’ and just leave it on the Kickr semi-permanently. It only needs a fork, front wheel, shifter and rear mech, cranks and seat-post plus saddle, bar etc and it doesn’t matter if the frame is cheap and nasty.