Can I use my eTap AXS 36T Max rear derailleur with the 10-44T XPLR cassette?

No. The SRAM RED, Force, and Rival wider gearing 36T Max rear derailleurs will work with 12-speed cassettes from 10-28T up to 10-36T only. These derailleurs are marked as “MAX 36T” on the back of the derailleur near the derailleur mounting bolt. They are not designed to clear the larger gear profile of the 10-44T cassette.