I pretty much reported this issue and sent some logs/tests to amd devs about warframe and amd stuttering with 6000 series
and finally its fixed, still have some microstuttering but compared to before its improved by a lot, i also did it with overwatch and wayfinder (still need test both games)
So guys if you are experiencing heavy stuttering after cleaning your shaders/updating drivers check lastest driver and tell us how works for you