As for the route of laying cables, each concept has its supporters and opponents, it is not for me to judge which is better and which is worse.
I do not need junction boxes, I connect everything under the accessories in deep (60mm) boxes using WAGO connectors.
I do not know what my colleague has experience in this matter, but if it is small, I recommend arranging at least two meetings with an electrician: the first where he will suggest and advise on the spot what and how to do, and the second where he will check how it was done and whether everything is OK
After some time, each installer develops his style as he likes, and I like the following: