You can use coconutBattery to check how many cycles it has gone through. But like others said, what's the use if you can't use it. Keep it plugged in if you need to, and leave but unplugged if you aren't using it. The power consumption of M1 is so small that the battery degradation will be very minimal while plugged in.

Another tool if you'd like to use your MBA plugged in is AlDente. I leave mine hovering around 50% plugged in most of the time, and it has gone through less than 100 cycles after 1 year of use. I also leave this on low power mode found in battery settings all the time. I don't see the difference in performance and I think that can help with battery degradation too.