Slow down whenever you feel like it, but never quit! Also, if you put your API key into wkstats, you might have an idea of where to slow down! They show how the % of kanji you can read from different sources based on your level.
Here’s the chart up to level 20:
You’ll be around 70-85% of kanji known, so you’ll know around 8 out of 10 words in a sentence.
There’s also some charts and staticians on WK who show you how much you learn each level, and which levels are the most efficient. This post by asutekku is from 2019, but is probably still relevant. Basically level 21 is where you learn the most. So maybe start slowing down after level 21?