Vapor barrier

Vapor barrier basement
I am renovating a single-family house built in 1976. The basement (only about 1/4 underground) is made of 20 cm concrete, the ground floor is a timber frame construction.
The finished rooms in the basement have 6 cm mineral wool inside (very loose, so that the air could circulate perfectly) + 8 cm gypsum wall + textured paint and no vapor barrier.
Accordingly, the mineral wool also looks like that!
Now I have glued 15 cm walkable mineral wool directly onto the concrete with PU foam, then – also with PU foam – a 1.5 cm OSB board.
(The new sand-lime brick windows have a Uw of 0.7). Everything was pressed during installation, so there is no air anywhere, OSB board joints are glued. The interior wall made of sand-lime brick adjacent to the concrete was routed out 15 cm along the concrete and filled with mineral wool. This way I have no thermal bridges anywhere.
The Sd-values are therefore from outside to inside 16 / 0.15 / 3.4.
To avoid moisture problems, I may now have to provide an additional vapor barrier on the inside. Now I am not sure which Sd-value would be optimal inside, so that both winter and summer are optimally resolved. Question: Can someone assess whether the above construction can do without an additional vapor barrier?
(I want to apply a synthetic plaster on the OSB board).

The OSB boards themselves can already act as a vapor barrier if they are properly sealed at the edges. Otherwise, you can use a regular foil.

However, I would be careful and have a dew point calculation of the wall done. Then it would be clear where and how you need to install the vapor barrier.

But of course, it would have been better to do that beforehand. However, it probably can't be changed now.