Deck migration from 1 nextcloud instance to a new one

Our very small non-profit organization had to migrate from a server to a new one.

We now have a new instance on a new server that is eventually secure.

We have so tables and so many cards and comments in this original deck that copying it manually is being impossible. Would anyone have an idea on how to migrate this deck? Only 3 users were using Deck app. If links to users were to be brocken, we wouldn’t be mad if we could at least restore the cards titles.

Any hints more than welcome