Luke fixes the Falcon’s malfunctions himself before Han can figure out what to do
Every time I see this complaint I wonder if people were paying attention. The Falcon has had a number of “upgrades” since Han last saw her, all of which Rey is familiar with (which makes sense, it being Plutt’s ship and her being good with tech stuff, she’s probably worked on it) and Han knows nothing about. One of those is a compressor which she bypasses. The comparison here makes little sense.
Also when did Han become an expert on fixing The Falcon? Was it in SW when the ship almost caught fire during the TIE Fighter escape or was it in ESB when he couldn’t fix the hyperdrive? Both of these things and the general condition of the ship leads me to believe that Han is just getting by but that’s just me.