I had a similar experience related to this in the past couple of months. My company issued me a Macbook, and forced an upgrade to Big Sur recently. I'd been working through the pandemic by plugging the laptop into a HDMI monitor using a USB-C-to-HDMI adapter from Anker (purchased on Amazon: https://www.amazon.com/dp/B07THJGZ9Z/). After updating to Big Sur, MacOS refused to recognize the Anker adapter with a notification "USB Accessories Disabled", and a note that it was using too much power. I did a few hours of research trying to figure out what the power draw actually was (with no monitor plugged in) and scoured specifications for other adapters in the hope that I could identify one before purchasing that might work, but found scant information published on the power draw of various adapters.

I never succeeded. I just use the Macbook with only the built-in display now.