GSE for Shadowlands has just hit Beta stage. It is feature complete. It should also be safe to try on Retail and Classic. If you are new to mods don’t try this please.
IF you wish to test on Retail or Classic could you please backup your GSE.lua file from the WTF directory. You will need the original version of this file to go back to 2.5.11
Please report on GitHub any problems or issues.