In the past two weeks I’ve been in the CCR many times. In my experience the busiest around 10ish until 3pm ish. Before 10 not busy at all most of the mornings and after 3pm gradually getting less busy and at 8pm usually just me and maybe 2 more passengers. I would have to add that even during the busy period I always find a place to settle down either in the high chair area or near the bar. Lunch at the restaurant can be busy and sometimes I’ve seen it full but as I said before you can order food anywhere in the lounge, you won’t get any different option. I do understand however that some sofa’s are quite low and not the great to have food there.
As of connection I almost always use the e-gates go to landside and go to the First Wing. I never had good experience with flight connection in T5 even before Covid.
The T5B lounge is great however food and drink wise not in par with CCR so even if I would able to use flight connection in T5B I would walk back to the CCR. It’s a nice and peaceful 10 min usually.