Is there still room for newbs?

I see a lot of gurus in my IG feed trying to convince me that I can make 6 figures on an Amazon store. My husband and I have a couple successful small businesses but we would like to make a 5 year plan toward more passive income.

It seems like every private label product is already out there, buyers are smarter than ever, advertising barely works, and the platform is saturated.

Is there any way to get a foothold as a newb?

Assume we have 150k starting capital and we want to make 250k within 5 years.

After the Amazon seller university, who are your favorite YouTubers to learn from?