Is it okay to leave my MacBook plugged in all the time?

Yes. Apple designed for this. Optimized Battery Charging (on by default) learns your schedule and holds the battery at around 80% until just before you need it, which is ideal for lithium-ion longevity. Worst case, battery health dips slightly faster after years of 24/7 plugging, but that’s still gentler than constant full cycles. Let the software handle it.