It's a bit disingenuous to present solutions like Tailscale as more secure than opening a VPN port on one's on machine. The latter solution should always be preferred when available just because you don't want your infrastructure to depend on a "free" service which might cease to be free tomorrow.

This is a more all-included and resilient system, especially for logging, than just opening a VPN port. I do a lot of corporate installs, and if we had a system like Tailscale then I would be in heaven. The amount of user-created systems are heinous in regards to security, and hard to setup and keep running. Tailscale lets you setup quickly, and reliably with minimal errors OOTB.

If you feel that tailscale will fold, or the free plan will be future limited, then you can drop in headscale which is a near 1:1 API open source tailscale central server.

If you always want to be open source and not rely on API changes or staying up to green on the headscale development (made by a third party), then you can set up netbird, which is both hosted (for free) as an alternative to Tailscale more tailored for developers, but they also open-sourced their entire stack, so you can always leave and use that on your own servers.

Things are much more unscrupulous than potentially ceasing to be free tomorrow. Nobody who values their privacy would ever route their network traffic through a 'free' service.