11-speed Shimano gear is pretty crap tbh. I upgraded from a 10-speed XT drivetrain to 11-speed and actually wanted the 10-speed back within a month. The 11-speed XT feels flimsy and plastic. In fact so does the Sram 11-speed stuff I’ve ridden! I’m beginning to think 11-speed is a bit of a waste of time on all fronts! I’m on Sram Eagle 12-speed now and its by far the best drivetrain I’ve ever used. Smooth, feels well built and so far hasn’t missed a beat. Walks all over all the 11-speed stuff and feels just as good as the 10-speed kit XTR kit used to love. If you’re dead set on upgrading I’d go GX Eagle with an X01 shifter and call it done!
I’ve got Guide RS brakes and had a set of RSC’s on bike for a while and I do like them. Shimano have truly cocked their brakes up in last few years, the XT M785’s I had on all my bikes for a few years were far better than the newer M8000’s and XTR’s I’ve tried. I’ve ridden dozens of sets of Shimano brakes on test bikes and I can count on one hand the amount that didn’t have a spongy feel and/or a crazily wandering bite point. Hope are nice as are the new Magura MT Sports, which look a bit of a bargain to be fair!
Overall I’d stick with what you’ve got or as I say, go for Eagle and a better set of Guides (RS or RSC) or try Hope/Magura.