To achieve wrist flexing towards the inside and towards the outside, and to loosen up and develop the articulations controlling the mallets in the shifts and movements of percussion, you should devote your time consistently to one specific study at a time.
Technique exercises are certainly not concert pieces, but they are real gymnastics which are absolutely essential for the acquisition of methods used in performance.
Doing these exercises therefore means getting down to a sort of daily training session, the results of which can be seen day after day. Which is like saying that time dedicated to technique study is never wasted because in any case what you put in you get back out with interest, like saving money in a bank.
As a general rule, it is a good idea to begin each exercise very slowly, even if you are able to do it quicker, because rushing things never leads to perfection.
The ancient Romans were well aware of this, and used to caution: "Hasten slowly!".
Since you are involved in a sort of daily training session, the planning of your study technique should be developed in various stages, beginning with the sequences, even for those who have already achieved proficiency in them.
If you proceed in this way, by a couple of months you should have mastered the entire cycle from start to finish.

The evolution of technique, for all daily exercises, consists of:

a) systematic study of nine sequences deriving from the drum, which, executed on the keyboard with suitable fingering, develop speed even in more awkward positions, touch sensitivity at various degrees of dynamic and sense of rhythm;

b) Restruck notes with alternate mallets and scales with arpeggios on the tonic;

c) Mixed interval scales for mallett opening and closing;

d) articulation exercises for the various types of tremolo and main trills;
technical brilliance exercises and three brief toccatas, to maintain and improve general agility.
Example (from a sequence for flexing the wrists)
(click here)