House from 1910 insulated from the inside

The ubakus calculator is not really suitable for old buildings. At best, it serves as a rough guide.

The calculator does not care about the year the house was built. You only need to know the wall structure. That is more the problem.
If you don't know the wall structure exactly, you play around a bit with the materials – in the end, it will be more or less irrelevant what kind of stone the exterior wall is made of, as this usually leads only to marginal differences.

The professional also uses the calculator (in the professional version).

P.S. No matter how I calculate the wall structure, ubakus outputs "No, that leads to moisture in the wall" for all variants.

what do you want with a diffusion-open foil? Something like that is only used as wind protection. OSB is vapor-tight if the joints are glued and bonded. The only thing I would do is to bond wood fiber boards over the entire surface and plaster them on the outside. An energy consultant costs more than the savings in the next few years and most have little knowledge and even less about old buildings.