I am having the same issue with Ubuntu 20.04 and i followed your suggested steps and such and it still does not work. However i am able to run 1.16.3 but not 1.8.9 nor optifine for 1.8.9
I am having the same issue with Ubuntu 20.04 and i followed your suggested steps and such and it still does not work. However i am able to run 1.16.3 but not 1.8.9 nor optifine for 1.8.9