Best case, worst case, and typical case are three different numbers.
Although the actual time on the road from leaving airport property to arriving on WDW property is less than 30 minutes, all sorts of other things can add up before and after. Many of these things are unpredictable.
It begins with the actual flight arrival arrival time at Orlando Int'l Airport. We've been off the plane 15 minutes before our scheduled arrival time. We've landed 3 hours late.
When getting our own bags at baggage claim, they've appeared within 5 minutes of us getting down to baggage claim. They've taken 60 minutes to arrive a few hours after a summer thunderstorm because the baggage handlers were still backed up. And they've taken 40 minutes for no apparent reason.
Using DME, we once checked in and walked directly onto a waiting motorcoach, which closed its door and drove off within a few minutes, with our resort then being the first stop. Another time, we must have been in line for more than a half hour; we then sat on the coach waiting to leave; and we were the last stop.
Usually renting a car is fairly quick, but there have been a few times when it's taken us over an hour to get a car (not at Orlando).
Several years ago, it took us 45 minutes in line before it was my turn to check in at our resort. Other times, no other guests were checking in at the time we got there. Last fall, they needed to call a help desk to put our annual passes on our MagicBands; it took about an hour to be resolved.
In other words, there's no easy number. Plan on 3 hours. Be delighted when it only takes 2 hours. If it takes 6 hours, just be happy your destination is WDW, not to a cruise ship that sailed without you.
Don't plan anything on your arrival day that will cost a lot money or cause a lot of disappointment if you don't arrive in time. That includes credit-card-guaranteed ADRs for your favorite restaurant, tickets for La Nouba, or anything that you can't reschedule if you miss it.