Weird issue with connecting to my own network using openvpn. Could read, but upload things stalled at 192KB. Exactly similar as to what this gy describes.
The solution, after a lot of trial and error, is to set only mssfix on the client. I've set it to 1300. I didn't need to set fragment as that would require a change to all clients. I found out that I could even increase it to 1364.
The cause appears to be that MTU path discovery is broken for an unknown reason. I'm perhaps behind an old wifi router, or perhaps there are other weird things in between.