If you have a Host then they would need to have the option to install Bettas
If your hosting your self using steamcmd and given you have done it before.
If you are willing to Google:- How to setup a Valheim steamcmd Betta server.

First you would need to Download and Install SteamCMD then Create A text doc with the Following and name it ValheimBetta_Install_Update.bat
You do the following
I made a batch file w/
@echo off steamcmd.exe +force_install_dir "C:\Your\Valheim\Folder" +login anonymous +app_update 896660 -beta public-test -betapassword yesimadebackups validate +quit