Global Chat + Portal between two Fabric Servers with Velocity Proxy

Hey, I have a survival world and a creative world, two different fabric servers behind a velocity proxy. I recently switched paper and the multiverse plugin because I wasn’t using many plugins and all I really cared about was using litematica schematics and world edit in the create world, and pasting schematics instantly only seemed possible with servux and fabric.

I’m now able to switch servers with the /server command, but I’m trying to find a way to establish a physical portal between the worlds. Any fabric mods I’ve found are either way outdated or archived. Is it true that the server command acts at the proxy layer, and because of that using command blocks to detect players walking into the portal, and then issuing the /server command on their behalf wouldn’t work?

I’m pretty new to this, so please forgive me if I’m wording this incorrectly or overlooking a simple solution 🫠 any guidance would be very appreciated

TLDR: how can I set up a portal to get from one fabric server to another, behind a velocity proxy layer?