I did something similar for the past month. I picked up grammar along the way while studying vocabulary and reading, but never went through a textbook. So I decided to go over all of N5 and N4 on Bunpro. 20 lessons a day for a month with 100-200 reviews a day. You can definitely power through it, but I wouldn’t recommend it if you’re short on time.
Working through N2 now and doing 5 lessons a day. Its definitely more manageable. On average I get 50-100 reviews a day, but keep in mind at least half of those are from all the lessons I did last month so realistically at this pace, you can expect <50 reviews a day.