It's totally fine! I understand something not meeting expectations. My goal it to have MiniMeters be as performant and stable as reasonably possible and any help testing is appreciated. I haven't yet received a message from you in the email I listed in the last message, nor a message on Discord, but once I get either of those I'll send you the latest test build to see if that addresses the issue. I also might have some troubleshooting steps. I don't know if it will be a night and day difference, but that level of usage is abnormal.
As a note, you are correct that MiniMeters isn't "sleeping" when audio stops. That is definitely something that could help and is something that should be trivial to implement at least in the audio thread.