Do it the normal way - instead of your current “port-based VLAN” approach where each VLAN has a bridge of its own, use vlan-filtering=yes on a single common bridge along with the corresponding settings in /interface bridge vlan and /interface bridge port, so you will be able to connect the device in the garage using a trunk port (or a trunk bond of multiple ports)
See this post of mine and the @pcunite’s one it refers to if Mikrotik documentation is not enough to set up the above.