I think the convenience factor depends on the timing of your flights and if you plan to go to WDW before or after the cruise and to some degree how much luggage you have and how many children.
Sailing from PC, we usually fly down the evening before and stay at the Hyatt inside MCO. I haven't done this since pre-covid but they used to offer to retrieve your luggage from baggage claim for like $10 and bring it to your room. They‘d handle your luggage the next day if you take
DCL transfers and get your bags onto transfers trucks. With private transfers we wait with our bags at the outdoor pick up area and our driver deals with our bags.
If you fly in early in the day, there’s no point in sitting around the airport. I’d want to stay somewhere else closer to fun things to do.
A rental car gives you freedom but I wouldn't call it convenient to have to cram bags yourself and make sure it’s big enough to hold all your luggage, possibly a stroller, etc. For me it’s not a timesaver compared to having someone pick us up when we want. If you keep the car at PC, you have to pay to park it there or make it a one way rental which means hauling all your bags onto the shuttle of the rental car company in PC.
For post cruise, we usually have a noon flight home. Our driver is waiting for us when we exit customs and we hop in, he loads our bags and get dropped off at the terminal.
We have tried it every which way you can and in general what is cheapest way is the least convenient. The most convenient is usually most expensive. The less we have to haul our luggage, the happier we are, especially on a 7-nt cruise.
ETA: oops! Just read OP is staying at WDW pre cruise. Ignore parts about staying at the Hyatt.