rear derailleur and shifter combo

I'm not sure as you'll need to give the specific model number of the shifter. But if it's mixing and matching Dyna-sis and Linkglide, then no, I'm pretty sure they're not compatible.

From a quick Google search:

"LinkGlide (LG) shifters and derailleurs have a different cable pull ratio than the older Dyna-Sys (HG) components, making them incompatible."

SLX SHIFT LEVER RIGHT CLAMP BAND 11s

As above, you need a LinkGlide shifter like this.

https://sportandleisure.com/products/shimano-deore-xt-sl-m8130-link-glide-shifter-11-speed-band-on?currency=GBP&variant=55934733910403&utm_source=google&utm_medium=cpc&utm_campaign=Google%20Shopping&stkn=7ec433c77e4d&gad_source=1&gad_campaignid=23014340359&gbraid=0AAAAADKtyDB78m704Wv1EeYZ6u8wqTwqQ&gclid=EAIaIQobChMI9Jie293qkAMVHJtQBh3NRQDNEAQYASABEgIux_D_BwE

I accidentally bought the xt linkglide derailleur from Banana industries.   I bought a 11 speed cues shifter to go with it.  You can use 11 speed hyper glide cassettes doesn't need to be the linkgllide one.