Building Copycats and launching them quickly in new markets

Hey everybody,

Thank you for having me.

I am looking to build my first app/tool/saas and I would like to start from copying a successful US one and launch it in minor EU Markets.

I am missing the 101 on how to fine the validated projects currently working in the US and how to replicate it. I was thinking to use Lovable or similar solutions.

Whats your advice?