I would be very surprised if they wouldn't fix all 50 filesystems.
In all projects I have worked on (which does not include the Linux kernel) submitting a merge request with changes that don't compile is an absolute no-go. What happens there is, that the CI pipeline runs, fails, and instead of a code review the person submitting the MR gets a note that their CI run failed, and they should fix it before re-opening the MR.
This. There is very little need for third-party tools, as long as you don't want to install a whole lot of games. After all, the installation process only happens once per game, and also without tools it doesn't take very long.
As a step-by-step guide: