Upon listening to many different R&B songs, I noticed that a few different songs used the same type of progression to achieve the stylistic sound. I jotted down some notes and after messing around with my guitar for a bit, I was able to transpose and come up with an easy to play progression on guitar that reflects the R&B style. The progression has a very stylistically R&B sound and can be manipulated in many ways for improvisation purposes. The progression is the following:
CMaj7-dmin7-amin7-D7-F-G-G7
The first two chords can be repeated numerous times before moving on. Here is a video of what it sounds like, with some embellishments included as well.
For the sake of improvising, I will share videos below on how to play these chords and how to embellish as well.