With a good MIDI sound source and some good MIDI techniques you can get tracks that rival RTs IMHO. RTs are great, I do use them, but MIDI is a lot more flexible. You can change notes, timing, sounds, etc with MIDI that you can't with RTs. I'm sure you already know this.

But there are a couple of catches. One is that good MIDI sound sources cost money. Generally the more money the better the control and sound. Another catch is there is a learning curve. Taking a BiaB MIDI track and playing in on an expensive MIDI sound source can sound terrible. You need to know the nuances of the instrument you are trying to emulate and how to achieve it via MIDI controls.

A plus is that MIDI sound sources can generate sounds that no acoustic instrument can produce. Pads used in smooth jazz or ambient music are a good example.

What I would do in your situation would be to get the free stuff first. There are free or very inexpensive sound sources like Kontakt Player, Sampletank 3 Player, Synthmaster player, KVR synths etc. Most all of these do allow MIDI CC changes so you can experiment and learn about MIDI controls. These do have excellent sounds included. I know that you can purchase other sounds for the Kontakt Player and the Synthmaster Player.

I hope this helps and good luck.

PS - self promotion - You might want to listen to some of my songs. They are almost exclusively MIDI with some organic guitar and bass parts added to some.

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware