Can this bow be self-supporting?

Good morning everyone, attached I am sending you the plans. Can anyone make sense of them? I have been trying to get a structural engineer for a long time. Unfortunately, they all seem to be too busy with such small projects at the moment. I would like to refer again to the statement from Hanghaus2000. He told me that the arch could have a load-bearing function and was probably built up around a wooden arch. That is understandable to me. However, a mason just told me that the facing bricks never have a load-bearing effect. Could you agree with that?

Yes. Precisely because they have right angles.

Yes. Especially because they have right angles.

What exactly do you mean now? :) So would you say that the bricks have no load-bearing effect?

If all bricks have right angles, they cannot carry the load; the mortar would have to carry it, adventurous :). If the arch were supposed to be load-bearing, the two radii of the arch would also have to be different; they do not match the width of the passage, one is too small, the other too large. I would also look for a lintel. In case of doubt, I would slip in a suitable gauge on the last centimeters of the vertically built section so that nothing falls during the vigorous removal. Basket arches used to be fashionable because not everyone could even draw them, much more stylish than round arches.

The question is whether the ceiling is load-bearing despite the additional load of a wall on top.

I would install a row of temporary supports on both sides, break the arch, and then install a steel beam as a lintel.

Afterwards, remove the temporary supports.

The reinforcement plans are not helpful because they are for the basement. Ground floor plans would be needed.
Regarding your question: yes, the arch can be load-bearing. An arch carries itself in such a way that a not insignificant horizontal load is generated on the walls. The two wall sections left and right of the opening could possibly absorb this load.
Actually, this is all just guessing. Remove the lintel completely from the plaster and take some pictures, then we can discuss further.