I think some responses are missing the point. Sure there can be workarounds. The issue is - prior to upgrading to Tahoe 26.1, the battery level always displayed for bluetooth devices when you clicked on the bluetooth icon in the top menu.
Now, it doesn't, also for me.
If Apple removed that, it seems to be a step backwards when they are a supposed to be one of the top tech companies. For making the investment in a Macbook, one would think one wouldn't have to then add more apps to monitor something like bluetooth device battery levels when the OS versions prior all did that.
Yes we can check it often to see where the battery level is, but that is how we did it before when the battery percentage displayed when clicking the bluetooth icon in the menu.