Have you tried with XMP/DOCP disabled for testing purposes?
3600 speeds on a 3000 series IMC is pushing it pretty good .. maybe handling 2 displays is enough to push it over the edge
I run an ASUS 27" 60hz 1080p secondary and a Samsung 27" 1440p 144hz 4ms primary on my 7900xt without issue .. first on my AM4 setup (5900x w/4x16GB 3600, x570 Taichi) and now on my AM5 setup
Just spit ball'n here