Softether VPN slow compared to OpenVPN


I have been searching for an solutions but could not find one that worked. I apologize in advance as this is my first experience with OpenWRT in Turris Omnia. That is, I am a noob who tries to fly before walk.

To describe my issue in short, I setup OpenVPN server using Frobis. This was easy. Then I followed the guide on installing Softether and was done successfully. This is where the trouble begins. I compared the speed between them. OpenVPN turns out to be 3X to 10X faster than Softether VPN. Then I searched all over the internet to find a solution. Unfortunately none worked to increase the speed on Softether VPN.

Could someone here help me out? Thank you so much in advance.

PS. I am a noobie who knows a few commands.