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"Also, don't know how much adjustment I've actually got without also moving the brake lever too far away."
Ok, I was confused by this bit. Well I'd try shifting it so it clears the grip entirely, anyway. And if your brake levers are pitched too far down, I'd rotate them up a bit so the shift lever can move forward also.
If my 11sp XT is anything to go by, the lever action is pretty light. The high end mechanical SRAM shifters have an adjustable lever angle, so might be worth considering, the shift feel is quite different. More of a wind up to a click, rather than having that sort of threshold force required
Have you got your shifter in-between the brake and grip? That can't possibly be comfortable. Move it inboard of the brake.
I have mine set up so the shift lever falls just at the inner edge of the grip.