On my server, players can’t use a portal that I’ve placed since it’s expert mode. They can use the zoom out method to teleport, but they can’t make anything in it.
I would love if there were a new portal able to be crafted by admins. When it is placed, players can use it as if they placed it – but they can’t remove it obviously.
It would be crafted the same way a normal portal would be crafted, and it would still have to be upgraded like a regular portal.