Ironically, the official launcher was working fine before, but I had to build the AUR OpenJDK 16 because MultiMC would not start MC version 1.17 without it, which was working fine through the official launcher with OpenJDK 11 from the official Manjaro repo. I don't know if that is related at all, but I am not sure what else I changed since then.
I have the same issue on Manjaro.
Ironically, the official launcher was working fine before, but I had to build the AUR OpenJDK 16 because MultiMC would not start MC version 1.17 without it, which was working fine through the official launcher with OpenJDK 11 from the official Manjaro repo. I don't know if that is related at all, but I am not sure what else I changed since then.