Insulating glass pane from the inside

Hello. I want to close one side of my conservatory because a large wall unit is to be placed there (I already have the permit). Can I insulate the glass pane (flat glass 12mm from 1986) from the inside? So insulation in front of it, then a vapor retarder with variable humidity in front of that, and then, so it is not visible, an OSB, MDF, plywood, particle board, etc.?

How do you come up with the idea of upgrading a conservatory from 1986 with 4-4-4 glazing through the insulation of a wall sufficiently to make it a year-round usable living space?

He is habitable all year round. He has underfloor heating etc. It's just about closing the wall so that a wall unit can be placed there without the windows behind being visible.