Job hopping for growth, what’s the catch

Hi, I am currently an IC Engineer (l5), and thinking about pros and cons of internal promo vs job switch for growth. I got upleveled from my previous company when I joined current role, and I had some ramp up time (6-12 months) to be comfortable with expectations. I might get promoted in a while (2-4 years?) internally, but I am thinking of trying externally again for next level role.

I believe I should be able to perform at next level with some ramp up time, so not sure if it’s worth to try to get internal promo.

For folks who have done this (couple of job switches for promo), what’s the downside of growing in same company vs keep switching for promo?

I am aware that hopping constantly is self correcting problem, I am asking what’s the downside assuming we get up level role at equivalent company?