Why don't you just try one cassette from the shop? 11 speed with the long cage shifts a lot better with the 36t cassette than with a 46t. Pretty sure I could still get a bigger or a smaller cassette as there's still some b-screw to play with. If anything, I'd expect AXS to shift better.
Not gonna work well, as the derailleur is designed specifically for 10-50, so it will shift like shit.