Ariane 7 is not due for anything. Its just some agencies playing around with ideas. There is no real plan for Ariane 7 and no authorization for anything.

Also, people need to understand that most of the Ariane 6 is just Ariane 5 ME. Lots of parts of the Ariane 6 had been in development long before the Ariane 6.

The new upper stage engine took 20+ years to develop.

It was very hard for ESA to even get funding for Ariane 6, many nations wanted to stick to Ariane 5 ME. It will be a long while until the authorize another 4 billion $ for a new rocket.