Yes and no.
I’m actually still in the midst of (slowly, sorry) migrating the VUMeter code over to a version that uses Python for its front-end. With Python in the mix, it’s much easier for anyone to modify the behaviour of the VUMeter and test it pretty much immediately.
You could brave the development version of VUMeter,
or you could modify the pHAT BEAT plugin of your existing version by editing: https://github.com/pimoroni/pivumeter/blob/master/src/devices/phat-beat.c#L88
Then running the installer again (from your edited local copy).
The plugins unfortunately get no information about how loud the music is, so the scaling factor can’t be (easily) adjusted automatically. I had an idea to use a slow moving-average to set the scale, but then instead switched over to using Python for the front-end, which makes it far easier to support long-term.