Always cracks me up if people ask in plural "we", anyhow.
Installing from AUR just requires the user to read some docs, since AUR is compiling from source by PKGBUILD.
Answer, you, rocky_iv, edit the PKGBUILD and remove systemd, this is a learning process.
That's a strange PKGBUILD (Assuming it's windscribe-v2-bin you are referring to as there is no windscribe package on the AUR).
The windscribe-v2-bin PKGBUILD downloads an actual Arch package from deploy.totallyacdn.com (whatever that is) and then makes a new package from it. Which seems pointless?
I suspect the systemd dependency maybe wrong?
I just downloaded it direct from the source and after extracting and running ldd recursively can not see any systemd libs being linked.
So you may be able to to install it by simply
sudo pacman -U https://deploy.totallyacdn.com/desktop-apps/2.9.9/windscribe_2.9.9_x86_64.pkg.tar.zst
However before you try that I suggest you research and check that deploy.totallyacdn.com is an official distribution channel for Windscribe. Because it could be anything.
It might work, it might not. I've no clue. It might be other networking aspects of systemd it relies on rather than direct links to libraries ?
I suppose the upside to using the AUR approach is you'll know when it needs updating if you use AUR helpers.
You just need to remove 'systemd' from the depends line in the PKGBUILD and build the package manually each time to update it.