translated so that all have an advantage, thanks to Velkerk
If cryptomator 1.5.15-2 from AUR repositories does not install correctly from Pamac type the following in console:
$ archlinux-java status
java-15-openjdk (default)
java-16-openjdk
java-8-openjdk/jre
Change the default.
$ sudo archlinux-java set java-16-openjdk
$ archlinux-java status
Available Java environments:
java-15-openjdk
java-16-openjdk (default)
java-8-openjdk/jre
And now you can install Cryptomator in the usual way from Pamac.