tl:dr; Tailscale easily sets up remote machines as though they were on your local network (VPN)
Tell me if this situation sounds familiar: you have a variety of machines, at home and at remote locations. All combinations: behind a proxy/NAT, connected directly, a mix of Linux and Mac/Windows systems, a mixture of physical hardware and cloud instances. You want these machines to behave like they're on a local network and to use them without jumping through hoops. You could access these machines with proxies like ngrok or other tunneling software like ssh, but that's complicated.
You could set up a VPN, but that is time consuming and difficult to manage. Setting up a VPN requires skill and is difficult to get right across host platforms or architectures.
Tailscale is an excellent, simple-to-setup and secure VPN, with clients available for all major systems and architectures. You use an existing authentication (like your Gmail address), download the client software for your platform, and authenticate by navigating to a web address. Setting it up is refreshingly simple. It even sets up a dns, so you can refer to your machines by their hostname: p31 can be used instead of the full VPN IP address like 100.107.137.29.
I've used a variety of VPN systems in the past; I've also set up my own tunnels using different providers; I've rolled my own tunnels from first principles. Compared to existing systems, Tailscale is easier to setup, efficient, and has great network performance. Network latencies are lower than traditional hub-and-spoke systems, which relay through a central server. If the central server is located far from both VPN'd machine, network performance is usually poor.
Right now I'm pinging machines that are behind a NAT, accessing web pages on a different physical network, all by referring to simple hostnames. There's arm32, arm64, x64, different operating systems, physical and cloud instances that all appear as a local Class-A network. This is like magic!
Tailscale is also great for working on projects on your cloud or local instance without exposing it to the wild Internet traffic.
Image courtesy: Wikipedia.