Got it working as well now
Looks like playing around with the options in “Configure InputStreamAdaptive” inside youtube -> settings -> MPEG-DASH did the trick.
Setting the Min.Bandwidth (Bit/s) to 10000000 and Max resolution for general and secure decoder to 1080p and stream selection to auto did the trick
I know that I will have to change this once I get a 4k tv ( since some people are claiming they got 4k working with youtube ) but for now this works for me
If anyone has any suggestions let me know.
Update: After looking into it a bit more I found out that Min.Bandwidth (Bit/s) can stay at 0 Only Proxy/Use for videos and inputstream.adaptive need to be enabled and installed