Yeah, swapped out grub for systemd-init on a running Arch system not too long ago. Arch is cool with it. Be sure not to make any really bad typos while you’ve not got a boot manager, of course.

The real advantage of a 120 Hz screen is that you get a much more graceful degradation if you dip below your fps target for a bit. If you’re targeting 30 fps but drop to 25, it still feels pretty smooth on a high-refresh screen, whereas that’s appallingly clunky on a low-refresh one. A “poor man’s gsync”, if you will.

After having used Grub for about twenty years (eek) I was uncertain about the alternatives, but systemd-boot is absurdly better. Much better configuration, much better documentation, fixes a while pile of bugs that Grub team had as “won’t fix” for years and years. No reason to ever go back.