There are some on here who look after installs with multiple users of varying expertise- with a range from system-designer to power-on-and-fader-up... particularly for HoW environments.
Two of the constant problems for the latter are the 'its too loud' AND 'its too quiet' issues. Getting in the Goldilocks zone can be hard for people who don't use systems frequently but still need to make it work for an audience.
Hence, the Goldilocks meter.
KISS principle UI.
Red for too loud. Yellow for too quiet. Green for just right.
Splits for >150 and <150Hz.
Two different punch-button settings for 'music' and 'voice' programme material.
Levels totally configurable in code- set once and forget, based on agreed 'that sounds fine' conversations you can have with the venue owners.
3-minute graph for 'it was too loud a minute ago...no, it wasn't' audience-at-desk conversations.
Totally user-proof: autoloads on a Pi, completely controlled from touchscreen UI.
Needs a RPI, a cheap USB sound card, and a Pi touchscreen. Total cost £30.
Printable mount instructions, commented code and install guide included at the link above
Let me know if it works for you or if you find it helpful...