UGH!!! Starter Issue. HELP!

If you have a lightweight flywheel, it's probably aluminum. ALL ring gears are pressed, not welded.

You have no choice. Get a new gear, or get a different flywheel.

Throw the flywheel in the freezer for awhile. Then lay it out of bricks/ concret block, and heat the outside of the gear with a torch. It should almost fall right off. Might have to help it by tapping around the edge with a punch and hammer.

However, since it has slipped, it may have tore up the flywheel enough that a new one won't hold, either. If this was a fairly new flywheel, I'd be crying to whoever sold it to you.