Music and Podcasts don't sync regularly using two Apple Watches

Hi all,

I use two AW on a daily basis - an Apple Watch 4 Nike+ when at home, during my workouts and to track sleep; and a Stainless Steel Apple Watch Series 3 for my working hours at the office. Both AW are paired with my iPhone XR using the option to automatically connect to any paired AW when you put it on and raise your wrist. My daily routine follows: when I get back from work I take off my Series 3 and put it on the charger while putting on Series 4 which was on the charger till then. Home stuff and going to bed with the AW 4 in order to track sleep. In the morning I go for a run and when I come home I switch watches again putting the Series 3 on while leaving the AW 4 on the charger. The problem is that both watches does not seem to be able to sync Music and Podcasts. Maybe the reason for this is because any of them doesn't have enough time being on the charger with the paired iPhone presenting, both devices connected to the same wifi network. In other words, when I put a watch on the charger the other active watch takes focus being paired to the iPhone and the other watch stays at home all by itself. Strange thing - sometimes watches are able to keep up and manage to sync content to some extend but this happens rarely and almost never to full. The issue is that I like listening to my podcasts and music while working out but the watch library is not updating. Is there something I can do to force the watch to sync? Yesterday I tried to leave my sport watch on the charger and not wearing the Series 3 hoping that the Series 4 will stay connected this way and sync. Didn't happen and I was surprised to see that even not putting on the other watch it somehow 'stole' the connection and became the paired one with the iPhone. I would appreciate some ideas. Of course, I prefer both watches being updated daily without me doing nothing about it :) Thanks.