how to tell if mouse is charging on iMac 24

It would be hard to check the Bluetooth menu mouse charging status while plugged in without using a separate mouse. Here is my charging Apple keyboard which shows the lightning bolt charging indicator:

Personally. I was thinking you could check the charge level of the mouse before plugging it in. Then plug it in for 10-15 mins or so, then unplug it to see if the charge level increased. If it has, it's been charging. 🧠

If you have the Bluetooth icon visible in the Menu Bar you can check its charge by clicking on it.

You're welcome.

Find any old USB mouse and use this to click on the Bluetooth Icon or in System Preferences while the wireless mouse is charging.