(I'm a diy user, frequent brief use plus some 'big days' when the kit is used a lot)
I've had a Bosch Blue pair - combi + impact - since 2016 and the original batteries are still surprisingly OK. On the basis of that limited experience I wlll probabaly stick with Bosch when the time comes to change.
I would always go for 2 x 2 ah rather than 5 ah - lighter and one can be on charge with one in use, and it takes seconds to swap. I can see that 5 ah would be useful for site or remote use.
During lockdown my daughter moved into her first house, 200 miles away form here and frustrating because I couldn't go help out, and wanted a combi drill. I advised her to get a decent brand becsause it becomes your core piece of kit and we ordered DeWalt online - main criterion, it was in stock. Maybe one of the rare occasions when a daughter has been delighted to get a combi drill for Christmas. Now I have used a bit it it's fine but somehow not as nice to handle as the Blue Bosch. Can't quite put my finger on why I don't like it as much. maybe there is a real difference betweeen their diy and trade options.