I am practicing chords and scales according to the chord progression and I find it difficult to make the transfer from technical exercises to creative improvisation.
Is there any method or idea that could help me make the shift?
I will be happy and grateful even with very small steps at the beginning.

I would say listen to as much jazz as possible. Soak it in. Then, find the music to some solos or just figure them out by ear. See how the pros do it. Then, study your scales, modes, etc. It takes time and experience, just like the technical excersises.

other than the above methods, i find it best to, when listing to music from a radio or something, justplay around. It takesa while to figure out "what sounds good" In marching band, about 1/4 of what i do is improv for exanple.