I’m afraid that Carbide Create doesn’t support such endmills.
My suggestion would be to do the math to calculate diameter at intended max cut depth (don’t measure w/ calipers, risk of damaging the cutting edge) and enter as a ball-nosed endmill with that diameter.
Then, I believe one can enter such tooling into CAMotics and get a reasonably accurate preview — based on that you should be able to decide if it’s worth trying the cut or no.
Best option for unsupported tooling is either manually coding toolpaths using a tool such as https://tplang.org/ (see https://wiki.shapeoko.com/index.php/Programming for other options), or finding a tool which does support the geometries in question. Not sure if Carbide Create will ever be that tool — check in on the wish list thread: Carbide Create Pro- What do you want to see?