OP, I was this guy, except I'm female. In the beginning, I'd be all about the communication, it's new, exciting and different - loved it.
Then as it progressed, actual dates, a steadier structure in my interaction with that person, my interest disappeared. The other person then became a 'oh yeah, I need to respond' sort of part of my list. I'm also very, very confident which would often leave the other person wanting to appear the same, I note you say 'I'm cool with this' a lot but you're clearly not.
My other issue was, in my head I'd be giving signals that I'm actually not interested (days and days without communication) but I didn't want to be the bad guy (or mature enough!) to tell the other person I didn't like them. I would want the other person to take the hint and stop pursuing me, that way they were the bad guy. But they often wouldn't. Mostly because I would say the right things at the right time, , again I was at fault.
The whole situation would often end up messy until the other person got fed up, even more confused and walked away.
However, when it mattered to me, when the other person mattered to me, the effort was there on my part, no matter what and I made the time and made them feel wanted and special.
(I'd like to add I was very immature and have grown a lot in the last 20 odd years).
He is rude to you, lack of manners isnt a communication issue, it's just RUDE.
He can give you a basic response or an explanation about his lack of communication but he's just leaving you hanging.
You have already said your communication styles do not align. That's not a great start.
I wouldn't take this any further because really, if he was completely into you, he'd be contacting you. You're worth that, especially at this early stage.
Also, if he is only using word such as 'lovely' 'nice' 'great' etc to describe you and his time with you, yeah - get rid.
Would you be ok with a friend or loved one being treated like this? If the answer is no, then you know what to do.