Is there a particular part of the GDPR that you find challenging?
I can see a few clear problems with this plan in general:
If you do this successfully at scale, and have any EU customers, the EU will eventually make a very good go at fining you - they fine lots of people (https://www.enforcementtracker.com/). If you attempt to actively refuse to pay fines from a governmental organization at this scale, there's a good chance you will personally get in legal very hot water. I would not recommend it.
Even ignoring this, GDPR is not just an EU thing. The UK, Switzerland, Canada, Brazil, Israel, South Korea, Argentina, Japan, New Zealand, Indonesia, Uraguay all have substantial data protection laws that are at least equivalent to the GDPR's requirements & penalties (i.e. formally recognized as providing GDPR-adequate protection by the EU). There are many other data protection laws elsewhere too that might not match GDPR, but do still include very significant requirements, e.g. in California & China.
You mention Lusha - notably they explicitly claim to be GDPR compliant (https://www.lusha.com/legal/gdpr/) and they're formally registered as a data broker in California under the CCPA there. I can't comment on whether they're right, but they certainly aren't trying to ignore GDPR & data protection entirely. Time will tell whether that works.
To be honest, I think you're fighting obvious prevailing strong currents. Even if there's technically a way to run a business ignoring data protection now, the direction of travel is clear and consistent globally (albeit at different speeds). Any loopholes are going to be steadily closed up, and blatantly collecting private data to profile & track people is going to be illegal for businesses everywhere in the not too distant future. It's not a good foundation for a business.
I would prioritise finding a way to build your business without using other people's data without consent. It's rarely impossible, it mostly just requires a change in mindset, and once you're used to it it's often not even particularly challenging.