Hi,I am not entirely sure of what the problem is but from the photos you have uploaded you are most likely indeed correct.It is indeed most Likely a connector problem on the board.Recently,While I was conducting a repair on An IPad Pro I accidentally removed a display flex cable too fast and it damaged the connector and now I am getting it repaired by a micro souldering shop near me.So I would suggest first trying to clean the phone up as from the photos the connectors look a bit dusty do not blow on it or use water You can instead used compressed air or any other approved cleaning method for electronics.If it still does not work you should take it to a local souldering shop to see if they can replace the connector on the logic board.