Seems it was just coincidence that it worked for while with the new power supply.
Now i am back to unusable high ping times since two days.

And again. These ping times i get after a fresh factory reset. No VPN… no USB wifi… just a fresh factory reset:

The hours i spent trying to get this this Glinet router to work are countless and devastating… weeks… I am done with that and frustrated.

For testing i bought a cheap 10USD extender from Tenda. And here we go. Works almost flawless. I won’t have VPN or routing with it. But at least i have internet and low ping rates and highb speeds!! The GL-MT300N failed to give me that.

I don’t know why it does not work for me. I love the idea of these Glinet devices. But i guess it doesn’t work for everyone.