Children's room in the attic planned too small?

We also have the following idea:

The extension will be divided into 2 children's rooms, which are then "only 6 sqm + maybe 1 sqm of creditable living space due to the slope" but the rooms are completely glazed at the front and have a room height up to the roof (i.e. including the attic).
There should be a loft bed when the little ones are big enough. The rooms would be accessible through a kind of walk-in closet each, which will be located in the "current house." (Walls cannot be moved towards the extension since they are exterior walls.)
There might then possibly fit a complete bathroom, a small master bedroom for apparently "just the bed," and a normal room at the front..

So far, these are all just ideas that still need to be checked by the architect within the next 4 weeks as soon as we have found a version we are satisfied with.

Proposal 1 is currently preferred because a shower could be built in there in terms of size.
In the variant from earlier that you prefer, there is really only enough space for a toilet and nothing more.

A shower is naturally an argument; it cannot be placed under the slant. How many square meters does the house have in total? How many bathrooms do you have downstairs?

Maybe it is helpful if you upload a dimensioned drawing of the fixed elements (load-bearing walls, staircase, etc.) with 1m line, 2m line and indication of the kneewall. Then maybe a few constructive suggestions will come up here that you have not considered yet.

:)

So it can look like below, I'll add it here as well :) Currently, the square meters are 80 at the bottom and 40 at the top... but if we remove the existing partition wall in the upper floor (currently at 2m), we reach a living area of approx. 145 sqm in total (taking into account the countable living area regarding the sloped ceilings) Jochen - I'll create a dimensioning shortly and then upload it ;)

And ground floor currently