How to improve the skills of a character? (Patreon)

Making a system of character development, we are faced with a small dilemma. As you could see in the screenshot earlier, Kira has many different skills that will gradually increase in the course of the game, which of course will affect the character's abilities in this or that field.

The question, in solving which we need your help, is the following: how do you think it will be better and more convenient to improve the skills of the character?