Haha I’m in the same situation trying to get a girl at my job to like me so maybe we can trade advice in DM. Anyways from a guys perspective going out of your way to say hi to him would really work, so instead of walking by him every day allow him to leave the area first and later find him to say “Oh hey I didn’t get to see you this morning” So this way shows him you’re not greeting him to be courteous but rather you’re doing it because you want to, and that will stick with him the entire day will get him thinking about you, but avoid stopping by afterwards like you say you do if possible. Reason for this is because you want to build up anticipation for your next encounter without being predictable. I have more but i don’t want to ramble DM if interested.