@SomeNetEngineer 

Both OpenVPN and Wireguard require you to use an IP, it will be possible to use a name very soon but I don't know the date. you can immediately use L2TP/Ipsec site to site, then you will be able to use fqdn, it is possible to set up L2TP so that it works as site to site.
on the server side you create a user and set up extension mode and on the client side you enable routing. then you have site to site as you wish, in this way you can also use policy route and route all traffic out on the remote site.

I recommend you read the documentation for the router or if you use a controller then read that documentation, it says in more detail how you can configure the various components

you can also use fqdn with IPsec site to site, but then you do not have the option to route all traffic out to the remote site as you wish.

Vote here https://community.tp-link.com/en/business/forum/topic/643876