A Filo Muro door is a slab that is flush with the wall. So I do not understand what the "shadow gap" refers to, if you are wanting to add a reveal around the door slab (which would defeat the purpose of the flush door slab).

It appears you have a thick layer of joint compound that will crack between the drywall and frame, but the details that Filo Muro provides do not call for that, the drywalll meets into the frame, not next to it.

by shadow gap i am referring to a skirting T shaped aluminium profile that will be inserted in the lower gap of the wall/plasterboard that has been cut out, exactly like the one in the pic below

You do not "cut out" for a recessed base. The wall is built that way from the beginning with the recess built that way. The way you are attemting is just going to make a big mess.

Check in with the special door provider. This is pretty specialized but it migh involve cutting out a section at jamb to fit the "base" detail.

Less is more and less costs a lot more to do.

You have a huge mess on that wall a lot more to be done there before trying to jerry rig something that is not possible in your situation maybe try circling the area you want to change.The whole point of these doors is no frame , no jamb so no clue how that relates to the pic you posted of the very bad drywall.

The cutout at the base of the drywall is for the shadow gap profile to be inserted in , just like in the pics below. You insert the aluminium profile and then putty to patch up the remaining space of a few milimeters. The issue is, i was hoping to go with the aluminium profile all the way to the door frame, but i am unable to do that, since it is cut at an angle. So, as things stand, i am thinking of just painting the door frame black, just like the shadow gap profile is, or add drywall over it again, and just paint the drywall in black, because i will be painting the lower part of the doorleaf in black to align it with the shadow gap profile and make a seamless transition (due to shadow gap profile being 23mm high, and the door leaf maybe only 7-10mm high from the floor)

I'm interpretting "shadow ga'p" as a recess in the wall where there would normally be wall base moulding.

"i am thinking of just painting the door frame black"

"i will be painting the lower part of the doorleaf in black"

Those are unfortunate details.

Initially, I was going to say the gap under the door should align with the reveal, but that would also require cutting the frame jamb as Jeffrey suggested already. You might be able to only cut the outer "lip/flange," which will allow the T reveal to extend past the side of the jamb (leaving the "door stop" face of the jamb intact), and meet the door slab edge. Your picture does not look like the frame extrusion shapes on the Filo Muro brochures, so I can't offer a more precise way of getting this to look intentional.

"Less is more and less costs a lot more to do."

Jeffrey is right on. Simple, clean design is actually very difficult to achieve and requires a lot of planning. I hope you detail this so that it does not waste the look of the base reveals and expensive doors.