Embark (LA) and debark (Miami) on the Joy on our recent cruise was sloooooow.
We had bus transfers to/from airport so that added another line to stand and wait along with customs/border before that. We rolled with the punches and enjoyed the cruise but we knew those processes were going to be bad. No issues catching flights because they were late in the evening but we laughed because we wondered what we would do with all our "extra time" in Miami........well, it was used getting off the ship, customs, bus transfer, etc.
We are used to driving to port and doing self-assist in Galveston or New Orleans which have been smooth.