Before removing the flywheel, I'd like to check the runout of the face. Indicator base on the block, needle on the face.

That dark spot looks about 180 from where the grinding marks are visible. Like the flywheel wobbles.

Be a good idea to check that on the new flywheel too. Who knows if the crank flange is bent. Unlikely but not impossible.

Bellhousing concentricty is important too.

There may be multiple little things adding up.