Good points..could also be that the door seals are degrading..letting humidity inside...they can be replaced fairly easily and inexpensively..
Refrigerators of the last 15 years or so are pretty much closed systems. You don’t see many with the cooling grids on the back any more. The more modern ones are more or less closed from a maintenance stand point: Cooling grids on the right side with a fan at right angle behind them that blows the exhaust back over and evaporation pan that catches the frost free melted water that it accumulates.
Keep the grids clean and the airflow increases. My wife often puts machine washed sneakers on the left side at the bottom to dry them.
Keep the dust and lint out of the bottom, keep the compartments from being blocked and they will work for a long time.
Your door seal suggestion is good also. I try to take a hot washcloth to them every once and a while to remove grime and buildup that allows moisture to escape too.
Have you done one recently?
I used to do it for a living. Open door, loosen screws behind gasket lip. pull off gasket. Slide new gasket lip behind inner retainer. Tighten screws. Use heat gun to remove wrinkles.
Not anymore. Doors w/ urethane insulation (most newer models) have to be taken off the cabinet. Then lay them on a flat surface, table etc. Remove all the screws, remove old gasket, reverse procedure to install new gasket.
Very much more difficult than older models. I've done one, that was enough.