Roof renovation of a 25-year-old house

Good morning,
We have bought a 25-year-old house and now want to renovate it for ourselves.
First, the roof should be renewed. It is a half-hipped roof. The house measures 8.99m x 14.55m (without overhangs).
Currently, 7/14 rafters are installed.
My idea would be:

[*]Remove tiles and battens
[*]Remove old insulation
[*]Double up with 6/8
[*]40mm wood fiber insulation board
[*]Counter battens 3/5 S10
[*]Battens 4/6 S10
[*]New covering

Then the house would be watertight from the outside for now, and work can continue inside.

[*]200mm clamp fleece
[*]PE film vapor barrier
[*]Battens 24/80
[*]Drywall

What do you think? Would this be acceptable by today's standards?

I would be very grateful for constructive feedback.

(Why) does the roof have to be replaced after only 25 years?

Because the pans do not look nice. And I want to have everything up to a good "current" standard once.

No one has an opinion?

Isn't the breathable membrane missing under the tiles? Oh, by the way, check if you can currently dispose of the old insulation wool. I heard that wool older than 2 years can no longer be disposed of so easily. Apparently, there is currently no disposal concept for this.

Economically certainly rather nonsense. What kind of roof is it? Is the room underneath developed?