Per the Arch Wiki:

The AUR is unsupported, so any packages you install are your responsibility to update, not pacman’s. If packages in the official repositories are updated, you will need to rebuild any AUR packages that depend on those libraries.

Arch Wiki - Arch User Repository

They have a whole wiki for the AUR.

Arch Wiki - Arch User Repository

To update the package, you use git to pull the latest branch code and repeat the process. You should double check if there are dependency changes though.

Like I said, its easier with a pacman wrapper, but not necessary.

You definitely do not need to use any pacman wrappers to build a package from the AUR. Those tools make it easy, yes, but are not required.

Building a package can be as simple as

• git clone AURpackagehere
• cd AURpackagehere
• makepkg -si

Pacman is the only standard package manager for Arch. Arch recommends against using third party package managers, including Yay.

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