Helping setting up inter-vlan routing for VyOS router with Arista and Cumulus switches

I currently have a small lab network setup with a VyOS router, and some Arista/Cumulus switches. There's a few VLANs setup, but as I understand it, any traffic between VLANs needs to pass via the VyOS router which incurs a performance penalty.

I'm trying to offload the inter-VLAN routing to the switches, if possible.

Here is a diagram of the existing as-built network - I haven't listed all the VLANs/clients, but just enough to get an idea:

https://i.imgur.com/euHysnn.png

On the VyOS router, I've created interfaces (vif's) for each VLAN, and each has its own subnet, and DHCP ranges. The router provides DHCP and DNS forwarding.

The router is connected to a Arista copper switch (port is a trunk port). There are some clients hanging directly off this on access ports, and then also other trunk ports to two downstream switches.

There are then two more downstream switches, connected via trunk ports.

I want to be able to route traffic, for example, between VLAN 12 off one switch, going to VLAN 20 on the other. I assume the Arista 7050TX-64 will do the routing now, right?

How do I go about setting that up?

Do I need to make any configuration changes on the VyOS side of things, or will that stay as is?

And is it possible to do this for only some of the VLANs, or does it have to be done for all VLANs on the network at once?

And how do I verify it's all behaving correctly?