Sometimes these issues happen because of the IP range you’re using. If your local network and your remote network both use the 192.168.x.x range, then there can be conflicts and issues like this. This is a thing that happens generally with VPNs, not sure how Tailscale specifically functions with this issue.
Even if that’s not what’s going on here, you might try setting up your remote node as an exit node, and configuring your local node to route all traffic through it. Theoretically that shouldn’t be necessary, and it will also slow down your traffic if you’re routing EVERYTHING through Tailscale. But it could work in a pinch.
Actually, I’m looking at Tailscale documentation now and I see that they recommend setting up subnet routers instead of exit nodes in most cases. Maybe go that route instead, that makes more sense to me. That way you’re only routing necessary traffic through the remote node, rather than everything.
The popular use for power delivery through a display cable is charging a laptop from your monitor; it’s already very common with Thunderbolt or USB-4 monitors. But 480W seems a bit overkill for that.