add custom reverb to iMovie (or QuickTime)

I'd like to add reverb to the voice track of a QuickTime Movie I recorded, and imported into iMovie.

I know I can click on the Audio Effects button and have a choice of Small Room, Medium Room, Large Room and Cathedral...frankly all of these suck. The Small and Medium sound like your in a tube, and the Large & Cathedral are way too heavy on the reverb return, not nearly enough on the dry send, so you hear too little of the clear original track and too much echo slapback.

There doesn't appear to be any 'percentage-slider' to increase/decrease the dry-to-wet effect incrementally (an easy add and bad omission, Apple.)

Is there a good third-party app that allows easy exporting of the QuickTime movie (with video or just the detached audio) to add customizable reverb/delay, then back into iMovie with the new effect?

Running a new Mac Studio OS Monterey with iMovie 10.3.1