In answer to the original question- the pace doesn’t change, but the volume changes greatly (creating a feeling of greatly increased pace.)
You have to get 90% of your kanji in your current level to Guru 1 or higher before in order to raise your level. So if you do reviews 3x a day at 9am, 1pm and 9pm, (and don’t get anything wrong), each lesson item will become guru 3.5 days later.
Radicals have to reach Guru before they unlock the appropriate kanji (the ones that raise your level.) So if you don’t get anything wrong, it would take ~ a week per level. I find 10days to be about normal for the lower levels, since I’m far from infallible : p I also expect that rate to slow as the workload increases.
The amount of stuff you get will increase significantly. I’ll be level 6 tomorrow, and I had over 100 reviews today, and that’s still the tip of the iceberg. The reason it starts you off slow is to get you to build strong habits, so that when it gets heavy you’ll already have a good pattern.
As a beginner I found this guide super useful by the way. My Journey of 368 days (+ The Ultimate Guide for WK 📖 ) - #2 by jprspereira