I am currently training a junior dev. We only see each other every other week for a few hours. His motivation is all that matters imo. He is learning very fast
Perhaps remote learning requires skill and attitude that prevent you from needing someone to frequently co-write code. I don't have much time to spare so I will only co-write code when the jr dev is literally stuck. The rest of the time I give general guidance and let him figure it out - " improve logging here, consume less resources here by doing xyz, improve readability, optionally use advanced pattern to help you out, etc ". I try to give an example of what I mean each time. Each time he cracks things he grows in confidence and motivation