Thunderbolt 2 display with thunderbolt 3 adapter abruptly stopped operating in clamshell mode

My MacBook Air M1 2020 was working fine with my Thunderbolt 2 display (using Thunderbolt 2 adapter) yesterday. Today it goes black when I close the lid on my Mac. I’ve tried restarting then removing and replugging display as mentioned in earlier Community conversations, no dice. Tried shutting down completely with it plugged in and then again plugging in after it starts. I’m operating on Sonoma 14.2.1.

No idea what’s happened or what to do next. Help, please?