Logitech K750 lag/no response on iMac

I have a Logitech K750 Solar Keyboard connected to my iMac (2019, with Monterey/12.0.1). It has been working great until the last few days. Now, it sporadically stops taking keystrokes - sometimes storing/buffering most; other times, completely losing. This is my second K750. The first started displaying this issue shortly after I got it and Logitech sent me a replacement. (This was on my previous, late 2013, iMac.) I kept the original keyboard as a backup. I pulled it out, let it charge, and paired it. It is having similar issues.

I have tried the usual troubleshooting... unpair/pair, make sure it's close (dongle is plugged into the back of my iMac and keyboard is about 10" away). As a side note, when it is working, I can sit back as far as 6' from the iMac and see no issues. I have also tried swapping dongles without relief.

Other notes... Since Logitech Control Center is no longer support, I downloaded Logi Options to pair/unpair the keyboard. I have a Logi M325 mouse paired along with both the newer and original keyboards. I don't see any issues with the mouse, but both keyboards are displaying the issue. It *appears* that if one acts up, switching to the other keyboard does not resolve the issue.

I love the feel and size of this keyboard, but it is very frustrating.