My goto strings are Spitfire Symphonic, Chamber, and Solo, but I’ve also used 8Dio Anthology and Intimate Studio Strings on occasions. Depends on what sound I’m going for.
Note in particular Spitfire Solo Strings: I usually use those as first chairs along with Symphonic or Chamber, to add more detail and control. Even just duplicating the ensemble tracks with automation and all for the first chairs can make a big difference.
The next step would obviously be to play the first chairs on actual instruments, which could probably do a lot to circumvents the limited articulations of sample libraries. Working on that, but I don’t have or play viola or double bass. Yet.