Low room height; build higher than approved?

But you have to plan for that .. and, 19.6 cm step height is already quite steep. You should also try it.

But you have to plan for that .. and, 19.6 cm step height is quite steep. You should try it as well.

We currently have 19-20 cm in our rental apartment (strangely varies depending on the step). So far, we haven't had any problems with it.

The staircase currently has 15 steps with 18.8/26. That should still work out with +8mm, right?

"Or" is the correct answer.
Besides, if you increase it, the windows would also need to grow, otherwise "the ceiling will cast shadows."

Caution: isolated aspect taken out of context:

We also have a step height of 19.5 cm and neither our 2-year-old nor older people have had any problems with it so far. DIN 18065 does not specify a range of 14-20 cm for nothing, within which one can move.

We have now decided on recessed ceiling spotlights (for a mere €3000 additional cost) and to keep the ceiling height of 2.43m.