You’re thinking PXE/netboot, which netinstall disks are often used for, but you can use them independently of netboot.

Generally you have a minimal disk or recovery partition that initiates boot and offers the package manager, basic file and disk utilities, and a script to install a list of important packages. Basically nothing else. A handful of distros offer them, but they’re easy to make too. I usually have one in a partition alongside by boot partition. This is very similar to the distros that offer a “recovery” boot option.

The point is that instead of downloading a static version of the OS at 2GB+ these days, you have a tiny boot disk that downloads all the latest and greatest versions of the files you need, or allows you to fix breakages. This is what MacOS and these Linux distros have been offering for years.