A few years back i did 3 months learning to improvise with my sax teacher and we only worked with the G Blues pentatonic scale and most of the work was similar to Johnny’s course.
There’s no short cut way around improvising, you have to know scales and chords and do all these related exercises.
The only problem with practicing improvising, you could be in danger of loosing your music sheet reading skills in terms of playing in time with music sheet backing tracks. So keep playing your music sheets and make sure you use a metronome with the improvisation work before using any loops.