Netbird doesn’t have proper network isolation, due to its shared policy space compared to one gateway interface per customer/organization. Which is not an issue if you are the only user, but if you are building a service for customers to use, and there’s a potential scale up, it will be an issue, either having multi account mode which will results in many resources you need to deploy or containers per customer, or, having them all shared policy that could potentially allow customer to customer access if misconfiguration happens, alternatively, building a gateway in the middle to broker it all but traffic must pass through which is operational cost plus extra latency, and even privacy concerns.