You don’t need a vlan for link.local Link-local address - Wikipedia ?
I am still trying to work out Matter, but if you have a Ip4 network and run the tools @ GitHub - project-chip/matter.js: A complete typescript implementation of the Matter protocol specification (https://buildwithmatter.com). Includes full support for controller, device, commissioning, secure communications, device types, and cluster definitions. such as matter.js/chip-testing at main · project-chip/matter.js · GitHub against HA then at least you know where things stand.
As are we talking Matter or the current implementation of the HA Matter Border Router.