Thanks @Wolf0
I am now using DwarfPool and their Stratum Proxy (found nothing else useable?) and it's working.

I am currently mining Eth on a Radeon RX 480 on Win 10 and wanted to ask if it's normal that my GPU load seems to jump from 100 to ~0 when a share gets submitted.
Is there any workaround? Do I need to change my settings? Or is this normal?`

Thanks for an Answer