Depends on your tariffs. In Europe JLCPCB is always an option for PCBs. But as soon you order things with components placed on them you'll go into a different tariff regime and it will be $$$ quickly.

Yeah duties are the silent killer for assemblies. Safest to go with "local" assembly houses that subcontract and make the true cost transparent.

While $100 a unit isn't bad, the $500 buy in is a tough pill to swallow for a solo hobbyist. This doesn't look super fun to hand assemble either though.