Most likely your SRAM 12 speed system has an XD/XDR freehub body (minimum cog size 10 teeth). The Zwift Hub has a Shimano Hyperglide freehub body (minimum cog size 11 teeth). A SRAM 12 speed XD/XDR cassette will not fit on a Hyperglide freehub. The SunRace 11 speed cassette from Zwift will probably work badly. The SunRace 12 speed cassette from Zwift will probably sort of work, but not perfectly with SRAM, because it has Shimano 12 speed spacing. The ideal solution is to get an XD/XDR freehub for whichever trainer you buy, so you can use a real SRAM 12 speed cassette.
You might be interested in this other recent thread on the subject