This one needs to be addressed separately as it will clear up a common misconception
AUR buildscripts THE PKGBUILD provides files not available in the official repo (Arch) and the guidelines are very strict.
→ See AUR submission guidelines - ArchWiki
The submitted
PKGBUILDs must not build applications already in any of the official binary repositories under any circumstances.
These guidelines states THE PKGBUILD must not provide files provided in/from the official repo.
This means THE PKGBUILD will never provide any file that replaces system files; this is valid for all branches of Manjaro and it is valid for Arch Linux.
Therefore THE PKGBUILD contains a depends=() array, stating which packages is required for the result to be usable.
If a package with the same name exist e.g. yay or pamac-cli - those packages will build from source and thus they will not (should not) interfere with normal operation of apps provided in the Manjaro repo.
Packages that use prebuilt deliverables, when the sources are available, must use the
-binsuffix. An exception to this is with Java. The AUR should not contain the binary tarball created by makepkg, nor should it contain the filelist.
If THE PKGBUILD provides precompiled binaries - the rules requires a -bin suffix to the package name e.g. paru-bin vs. paru where the latter is being compiled locally.
Because the source for e.g. google-chrome is not available the -bin suffix is not required.