I think it’s fine using it plugged in a long period of time but just make sure to use the battery from time to time. I use it plugged in most of weekdays and on weekends I use its battery at least once.
As any Lithium battery it does not like to be empty but also it does not like to be full either for long periods of time. They feel best when they carry a charge in between 20% and 80%. Actually the optimal storage charge is at 40%.
It is a good practice to run a cycle of battery from time to time (maybe once a week would be good). Avoid though discharging to 0%, I believe the software is protecting against that anyway.