That's a good topic that could be developed into a series of progressive lessons.
I think early in the journey, you discover some relatively simple stylistic tricks, like alternating the bass lines, side-slipping into chords, grace-notes with hammers and pulls, syncopated strumming patterns or chromatic walk downs to add a little variety.
But it can get more complex, using pedal-tones, walking bass lines, back-cycling the cycle of fifths, tritone-subs and fitting chord and melody together, for self-accompaniment within a fuller soundscape.
I think these topics are covered here but not all under one roof so to speak, of "playing by yourself".
It seems like you're taking in the usual suspects: scales, arpeggios, swung bass line. The thing about scales is they tend to take you away from thinking about the underlying chords. In that sense, I'd try to find the collection of 3rds and 7ths for all the chords in your progression, THEN add in the rest of the triad and any other scale or color tones and experiment.
The blues scale is fine for wailing away, but you really need to add in the rest of the harmonic information to make lines that aren't just wailing and bending. (at least that is my downfall, wailing and bending aimlessly)
The other thing that is helpful is to learn how to play the melody of the song. Use those notes, too, in order to quote the identity of the song when necessary or to guide you back to a favorite chord in the song where you're more comfortable improvising.