Using a MacBook Pro 14 M1 mostly at a desk all day not doing any powerful tasks. Is it a good idea to use a 20W charger so it charger slowly and I'm not using it at 100% plunged in too much. Im thinking about the battery health.
Would stick with at least 30W. If you are connected to power for an extended period, macOS will put charging on hold. But if your power adapter is too low, it may have to dip into battery.
Think about battery health the same way you think about spark plug health in your car. Don't. Seriously, don't. The battery doesn't need special thought or attention.