QGIS 3.18.3: Reshape Feature - Cut from Polygon with Ellipse

I have basic polygon/rectangle which, I would like to cut part of it using Reshape Feature. All works good when, I do the reshape by drawing another polygon, which cuts parts of my basic polygon/rectangle.
I am looking for a way to perform the cut with ellipse.

Since QGIS allows to draw only polygons when Reshape Features mode is enabled – I am would like to search for the help of the community.