Worlr of Warcraft low shadow quality

i have a question about the shadow-quality in WoW. If i set them on low, everything is working fine, if i set the quality to medium or higher, i get a higher shadow-quality and they look really nice, but i get some stripes from left to right, and they let everything look crappy. Is there a possibility to fix that? My system-settings:
OS: Ubuntu 20.04 focal
Kernel: x86_64 Linux 5.4.0-52-generic
CPU: AMD Ryzen 3 3100 4-Core @ 8x 3,6GHz
GPU: Radeon RX 570 Series (POLARIS10, DRM 3.35.0, 5.4.0-52-generic, LLVM 11.0.0)
RAM: 16gb

Thanks for help!

In game settings change graphic API to DX 11 Legacy and check if the issue still exists.

the issue is a lot better but still there - maybe its ok like that. thx for help