Steel beam visible in the corner

Hello,

in our new building, we have a corner window with a steel beam.
From the flange plate 20 cm x 20 cm, a small piece about 5 cm x 5 cm protrudes into the living room.

Until yesterday, I assumed that it could probably be cut away by burning.
Now the metalworker says that because of the heat, the roller shutter box would also burn.

Unfortunately, you can't get into the corner with an angle grinder. I also don't want to lower the ceiling or something like that.

The flange plate of the steel beam is about 2 cm thick.

Does anyone maybe have an idea how to make this corner straight?

Thank you very much in advance.

Best regards
Kadir

Is the ceiling no longer plastered? Otherwise, just paint it white, and it won't be noticeable anymore.

The ceiling will be plastered and then wallpapered with painter's fleece. I would like to have it straight, otherwise I always get annoyed when I see it.

Hang a pot with a hanging plant there. Or a spotlight or a curtain rod and curtain.

Clever flex and get rid of it. Before that, tape off all the windows because the sparks destroy the windows.

Aren't there metal saw blades for the "Multitool" as well? That way, you could work directly in the corner.