Hi! I feel quite guilty as I text back extremely late. I don't know whether it can apply to your boyfriend, but from my personal experience, sometimes I just don't want any social interaction. It takes effort, and sometimes I'm just really tired, or I know that if I reply, I would have to start a conversation when I'm only on a 5 minute break. I personally just need periodic space, and I will reply to people in my own time.
However, I can see your point, maybe both of you can reach a compromise? Both of you seem to be extremely frustrated with the situation at hand, so it seems as though you might need to schedule a time to video call him. Try not to raise your voice, and try to understand his side. Ask him for his perspective, and listen. (that's what I regret not doing more often)
Long-distance is taxing. And based on how long you guys have been together, it seems as though you guys have put in a lot of effort to sustain it. You might need to give him more space, as it seems like what he wants, but it's an assumption from my end as well. Listen to what he wants, but also try to put forth your points in a calm manner. You also have wants to be addressed within this relationship as well, and it's going to become more strained if things aren't talked out.
I hope that everything works out for y'all though! x