Is there a way to uniformly increase the volume values of all events that are foldered in FMOD by 1dB?

The quantity is too large to adjust each event one by one…

What do you mean by “foldered?” It’s not a verb I’ve seen before.

Have you tried setting project’s master bus volume fader to +1 dB?

Have you considered using the Reaper batch file converter to apply a +1 db volume change to all audio files?

Otherwise, I would look into scripting in FMOD Studio.

Another possible solution would be to assign all the events you want to adjust to a VCA, and apply the adjustment to the VCA.