Here are three articles you should read:
If you follow the advice, it suggests that if you use it regularly connected to a charger (dock or otherwise) it’ll only charge to 80% which would maximise the value of the battery life (versus it being constantly charged to 100%
When they talk about not charging it regularly to 100% they mean doing that then powering it down and leaving it charged to 100% as this damages the battery. If your MacBook is on, macOS will manage this for you.
I can’t easily find anything which would definitely address leaving a laptop connected all of the time while using it.