I have two bull terriers, one (pictured) that is 65lbs and one that is 45 lbs. They're strong dogs and can be a little nervous with the idea of getting in and out of a RTT by latter. Luckily, they know not to jump! (sorta)
What I find works best is to exit first and stand on the latter facing inside the tent so that I am roughly eye level with the dog. I put their two front paws on my shoulder (one paw on each shoulder) and slowly scoot the dog forward with my right arm while cradling around their butt/tail. This helps them feel fully supported and it holds them tight against you where they do not really have the leverage to squirm or push off.
I did make the mistake the very last time I got out of our tent by being too low on the latter and the back paws got caught between the mattress and the lower area where the door flap zippers shut. The larger dog decided to try and jump onto/over my shoulder, making me twist my back backward and to the side in order to keep him from going over my shoulder and us/myself falling off the ladder. I felt that one for the better part of a week.
It's doable, just take your time and make your dog feel safe in order to minimize the struggle while you are trying hold them, hold the latter, and safely walk down it.