High dosage is not for your daily intake
It’s called a loading phase to quickly saturate the tissues i.e for a week or so for someone who never took the creatine. You can absolutely skip this.
I wouldn’t go higher than 10g daily on a regular basis.
I personally take 7.5g for the last couple of years.
The entire point is that >10G is justified if you're going for cognitive effects. For muscles you don't need to go above 5G. For brain, >15G.