Welcome to the Manjaro community @robochocobo
Have you had a look at AUR (en) - pulsemeeter? You could also try AUR (en) - pulsemeeter-git, which should install the latest version from git.
The original spiel from 4 years ago: Pulsemeeter, a voicemeeter alternative for linux : r/linuxaudio
You can build pulsemeeter either via the Pamac GUI (make sure the AUR is enabled in the settings), or to do it via the command line:
pamac build pulsemeeter
To build the latest git version:
pamac build pulsemeeter-git
Note: Do not use sudo with the above commands - pamac will prompt you for your password when required.