Description:
I compiled this package by myself just downloading the PKGBUILD and removing the qt5-webengine dep. The only difference with the actual package is that, to do the first login, your browser opens the login page instead of the webengine view.

ref: https://github.com/nextcloud/desktop/issues/932

This way you have a package without the huge webengine dep that is never used during the usual workflow and it is actually needed just for the first time login.

I'm actually using this package in this way since.. a lot of time ... without any issues.