I guess yay is an easy solution, but it's not very clean, at least from what I remember and just checked. It might be fine for single machines, but since it doesn't build in a clean chroot, you can never be sure that the claimed dependencies are actually complete, and as such, a package built with yay on one machine doesn't necessarily work on another, even for the same processor type (portability might not be possible anyways if you build with -march=native). It also doesn't handle automatic rebuilds for necessary .so-bumps, but this is generally non-trivial to solve AFAIK.

When I still used Arch exclusively, I had my own repository set up via aurutils on a remote server, granted this doesn't handle .so-bumps by itself either but at least you get somewhat clean packages every time, and you'll start to notice how many AUR packages are actually broken, with the most common occurrence being git not listed as a makedepends for packages that retrieve their data via Git because everyone using the AUR has it installed anyways to access anything on there. Granted this is a non-issue in practice but it's not the only one.