Static Route between two Zyxel Routers

I have a Zyxel USG Flex 700 that I use for my office network

I have a Zyxel ATP 800 that I use to manage my remote switches in the field

Both of these routers are mounted in the same rack. Right now, I have a VPN configured so that I can access my management network of the 800 from the internal office network of the 700.

However, since these two routers are side by side I would like to just use an ethernet cable between two of the LAN ports on each router to accomplish this rather than using a VPN since they are side by side.

The reason for using a Policy Route or Static Route, I am not sure which is best to use, is because we have VPNs configured from our home routers to access out internal office network on the Zyxel 700 router, so we can login to office equipment remotely, but this does not also allow me to access the management network of the 800 router.

What is the best way to go about doing this? Say I want to create a static route for networks to connect from router to router on LAN port 10 of each router. So just run an ethernet cable from port 10 of router 700 to port 10 of router 800.

I do know configuring a static route takes only a few settings and a policy router takes more configuration, so which is best for what I am wanting to accomplish?

Here are some of my main questions because I am ignorant on the subject completely:

what router do I set the static route on to make it work? or do I set it on both? or set the static route on one router and than set policy control rules on the other to allow the static route to work?