Shimano GRX shifter with 11-speed mountain derailleur

[DSmi]

Hey all,

My CX/Gravel bike came with a Shimano GRX-810 (1x) drivetrain. The derailleur has a 34T max cog and, living in a flatter area, it's more than fine but I'm planning on getting in some climbing-heavy gravel rides later this year so was looking to get something that can take more teeth in the rear. A little digging around has identified the XTR-M9000GS, another 11-speed RD, as a viable option but am unsure if a road shifter will be compatible with the mountain derailleur due to cable pull, etc.

Logic, to me, would dictate that they are cross compatible as both are 11-speed systems. Would my best bet be to keep digging for the long-cage GRX derailleur or would the XTR suffice?
Thanks in advance!

[ReapThaWhirlwind]

11 Speed are said to be compatible.

10 Speed Dynasys is said to be not compatible, but I matched it to a Dura Ace 10 speed and the only reason I got skipped gears was because I installed a low spacer on the cassette. The hub is an old Altus, with an 8-10 Speed freehub body. I totally forgot that the low spacer is only for installing 9/10 speed cassettes on an 11 speed freehub body.