Contrary to what someone said, you don’t have to do all the new kanji upon level up right away - just the new radicals. But you DO need to have done them by the time the radicals get guru’d at the latest (if you are trying to minimize level up time).
First few levels are easier and paced differently, you need to go through a few levels and several weeks before you get a credible idea of what you can and want to handle.
For the past 5 months, I’ve done 20 lessons or more per day with only 2 days being exceptions (90% of time 20 lessons, 10% 25 or 30). I essentially level up the fastest you can without making some drastic changes (min. time is 6 days 20 hours, My avg. is 7 days 20 hours, but it’s been on a downward trend for months) like setting alarms to wake me up for reviews in the middle of the night. Also I do some reviews in bathroom at work and at lunch, but obviously can’t always stop what I’m doing for reviews).
The 20 lesson per day also basically ensures that your vocabulary will never be more than maybe a half level behind, and you can do 25/30 for a day or two to catch up. Some people abuse the reorder script and fall drastically behind on vocab, but if you are consistent, you can still level up quickly and not fall behind.
tl;dr You get out what you put in. “Wanting” to level/learn quickly isn’t enough - have to be willing to put the time and effort in to match it.