Can I do both Amazon print on demand and private label with one seller account?

I would like to sell shirts and mugs on Amazon by connecting Printify/Printful to my seller account. However, in the future, I would also like to start a private label once I have capital already (that is different from the shirts niche so it must have a different storefront.) Is it possible to do with only one seller account? I would like to abide by amazon’s regulations.

I know Amazon has an amazon merch platform, but I got rejected so I think connecting a third party print on demand platform to my account is the option left.