Nice pictures and thanks for making an effort to describe the problem. This subject has been discussed, sometimes at length since January 2023 with the subject of WD Discovery being declared EOL. Basically the question can be summarized like this:
People want to be able to connect to private resources from anywhere in a highly secure way with relatively low cost or for free. What is the most practical ways to do this? The answer currently is some kind of peer-to-peer mesh VPN technologies and this is where ZeroTier and Tailscale which are two services provided free of charge for personal use come in.
Here is a link to such a discussion provided by Tailscale comparing the similarities:
In practice, Tailscale is a little easier to set up and provide a little more functionality than Zerotier and one such example was offered back in January 2023 in this subforum with an installation of Tailscale and its subnet router allowing remote sharing (eg across geo-location and subnets) with multi-factor authentication and end to end encryption using a My Cloud Home device for example mch4 shown. The Windows desktop shown is in one location, connected to a remote subnet in another location using 2 ISPs and sharing folders in a highly secure way, free of charge, thanks to Tailscale. No Western Digital cloud servers are required for authentication or end to end encryption.
