OTT make things easy as it run all the time (can be set to launch silently on Windows start) in the tray bar and allow you to make profile for each game. The profile is applied only when it detect the executable launch. If you want to change something, you have to fully exit MSFS, change profile, and relaunch MSFS.
Oculus Debug Tool changes will work for all application launched in VR right after, and need to stay open during gameplay. it have the same caveat, you have to exit VR (but can stay inside MSFS, just switch on monitor view), ALT-TAB and make change in ODT and switch back to VR.
So you don’t need both.
When you know which settings you like, just update the OTT profile, or, like me who don’t use anymore OTT, use ODT before launching the sim or better, launch it command line equivalent Oculusdebugtoolcli.exe with a txt with your settings as parameters.
Old post I wrote about this method: