Assumes that the drawing has been followed and the column has been built in bond with the basement exterior wall.
The two walls to the right (boiler room walls?) have the same function as the column, which is to withstand earth pressure.
A concrete slab with a span of 3.6m does not need any supporting braces from above.
One solution would be to demolish the retrofitted wall and build a wall with, for example, 12cm lecasten./MLj