I try to train daily and usually doing

rowing exercises (to make my hip movement swifter and more powerful), tenkan exercises, and other kata relevant to the techniques I learned from a prior lesson. Typically, this training system amounts to 20-30 minutes. Is this sufficient enough for improvement?

(Oh, and for anybody who's wondering, I train once a week but for three hours. My sensei plans to commit to teaching twice a week.)

Lorel Latorilla wrote: Is this sufficient enough for improvement?

IMHO, no one can answer that question without seeing you and knowing where you started. Ask your Sensei if you are improving. The best way to improve is to stay aware and enjoy the workout without thinking much about improvement. It takes time. Don't be in any rush. To improve the most, improve slowly.

Thanks for the advice.

Will deeply consider it.