Is it possible to level a sloped loggia floor with beams?

There is a bay window with floor-to-ceiling glazing, sandwich floor and glass roof (of course). There is no lattice (parapet), the floor slab (just like above us) is thin – about 80-100 mm. The floor slopes towards the street (apparently to drain water), a slope of about 50 mm in a width of 770 mm. I will level the floor with beams to insulate it a bit with wool, and put waterproof chipboard on top. The loggia will be cold, because it is small and has no purpose. It is the slope of the floor that gives me trouble with the beams, and I have my doubts. If I use 0 for the beams (ie where -50, I use 0 and where 0, it remains because the beams are offset from the wall), that leaves about 25 mm, in which I will install a 22 mm thick waterproof chipboard. If you do everything this way, the finished floor will extend to the plastic glazing profile just below the brace. And if you put the layer higher (which is better for leveling the floor in the apartment and on the loggia), the finished floor will come above the plastic profile and glazing bead – in the sandwich. So the floor would have to be sawed through all the irregularities of the plastic windows, which seems to me very difficult, and the neighborhood itself, in my opinion, would not look good. Also, it's not clear how to close the joint – you can't put a skirting board over it.... Maybe you can tell me how to make such a joint or how to get around this problem.