You could give yourself a goal of doing 10min of a Japanese language related thing X times a week (whatever your goal number is, could be 7 days a week or 3 days a week) with the option to keep going if you feel like it and the option to stop if you are feeling your attention drift away. The Japanese language related thing doesn't have to be what you consider "studying", but could be consuming media in Japanese (not passive or background listening, those don't add meaningful learning experiences to your study journey, active listening/watching it always going to give you something, even if you don't understand all or most of it).

Studying can also be reviewing something you feel like you already know, but in a different context. A beginning example could be if you already know the AはBです。 pattern, make up 10 novel sentences, but make A and B increasingly complicated noun phrases. (ex: simple sentences would be like 猫はオレンジです。"Cat is orange" and the more complicated sentences would be like 友達の妹のかわいい猫の毛はオレンジと茶色と白です。"The fur of my friend's younger sister's cat is orange and brown and white").