Personally I don’t use bunpro solely. It’s a nice compliment to my regular routine of full immersion reading and watching, while mining vocab and sometimes phrases for anki. Usually 1-2 hours in the evening and I do 10-30 mins of anki as soon as I can in the day.
I probably do about 10 bunpro reviews a day and a few grammar points a week. Usually I just add them as I encounter them in the wild.
It took a while to get to this point where I can confidently consume Japanese media regularly for hours on end but the sooner you start, the better.
I’d say if you’re lvl 30-50 in bunpro you could easily transition to immersion and quickly acquire Japanese. After a certain level straight up studying has diminishing returns. You have to start using the language for something or it will just get more and more difficult to stay motivated.