Macbook Air - Charging port doubling as thunderbolt bridge port

I have two macbook airs (M1 and M2) that I use at work. I connect them through thunderbolt bridge port using a usb-c to usb-c cable. I am concerned that one of my MacBook airs is showing at 100% but I am leaving it connected because I need it for the extended display. I tried doing some research and was told to turn off the optimized battery life setting (not sure if that was the right thing to do or not) and either way the battery symbol up top stll shows as if it is charging (has a lightning bolt on the battery symbol). Does this mean that my macbook air is still charging putting my battery and battery life at risk of damage due to over-charging?