Looking to fit a 12 speed XT8100 shifter to SRAM brakes.

Problem solvers mismatch adapter 2.2 is for iSpec 2

They sell a separate mount band that comes in different models for ISpec 2 and Ispec EV but I thought the iSpec EV differences were on the brake lever not the shifter (theres more range of adjustment)

You could try Wooftooth:

ShiftMount

I use their Shiftmount for Sram shifter to Shimano brakes and it seems well made and makes the bars look nice and clean.