Experience plays a lot into it. I know I met my BF on tinder too and our first date we hugged hellos and bye but that was it. I was super nervous to initiate anything and so was he. Second date, similar thing, we went to see a movie with one of his friends. It was late at night and i had to work the next day so we hugged bye again and left. He texted me when he got home safe and I invited him over, when he came over we talked for hours before he finally started to initiate some contact. I’d say try initiating contact, 4 dates in I’m sure he’s thinking the same thing, and if he just wants to be friends I’d imagine he would have told you by now.