https://headscale.net/stable/about/faq/#scaling-how-many-cli...

> Scaling / How many clients does Headscale support? > It depends. As often stated, Headscale is not enterprise software and our focus is homelabbers and self-hosters. Of course, we do not prevent people from using it in a commercial/professional setting and often get questions about scaling. > Please note that when Headscale is developed, performance is not part of the consideration as the main audience is considered to be users with a modest amount of devices. We focus on correctness and feature parity with Tailscale SaaS over time. [...] > Headscale calculates a map of all nodes that need to talk to each other, creating this "world map" requires a lot of CPU time. When an event that requires changes to this map happens, the whole "world" is recalculated, and a new "world map" is created for every node in the network. [...] > Headscale will start to struggle when [there are] e.g. many nodes with frequent changes will cause the resource usage to remain constantly high. In the worst case scenario, the queue of nodes waiting for their map will grow to a point where Headscale never will be able to catch up, and nodes will never learn about the current state of the world.

I find that quite interesting and it is one of the reasons I've not really considered trying out Headscale myself.

Why? Makes perfect sense to me. Designing a product with a specific use case in mind is good. When you've got the limited resources of am open source volunteer project, trying to solve every problem is a recipe for burnout. If it can even be done.