My speeds are quite good with Mullvad regardless of protocol. I pay for 500/500 to my ISP.
Wireguard
View attachment 1818583
OpenVPN
View attachment 1818584
not bad but seems there is about 100Mbps hit with OpenVPN. I am guessing you are using a close by server.
EDIT: Just noticed your location is in Sweden, thats where the Mullvad HQ is 🤣🤣 obviously you will get the best of speeds. That doesn't mean reaching a further server say like USA is going to be any worse