barking rear brake???

I think you have a small dog caught up in there. Try shoe him away with the garden hose.

Or

Check the pistons aren’t seized, the sliding pins aren’t sloppy & seizing, the pad pins aren’t ridged.
The disc isn’t warped.

Take the cap off the MC & check the rubber inner isn’t ripped & the breather isn’t clogged. Check the pedal doesn’t bind on anything & isn’t adjusted such that the return hole is closed (ie it has enough slack).

take the caliper off and check for movement . i had a noise and there was mud and a twig packed up above the pads that i had to clean out .