Welcome to the good ol days, no auto defrost on rv refrigerators.
We don't wait till it gets bad.
Empty the freezer then soak a towel in hot
hot water, wipe the frost till it's gone or till the towel starts freezing, resoak and do it again and again if needed.
Load freezer and keep the door closed as long as possible.
Takes us about 10 minutes
Edit: tell "kids"
stay OUT of the freezer!!"