Repair tech at HD says shaft likely bent and bearings are grinding. If he's right is the mower salvageable or is it a lost cause? He estimated $300 to repair - just the parts (new motor). If that's true then I'm better off buying a new mower. Does that estimate seem out of line?
What is his estimate based on? If he knows the cost of the parts then he should be able to tell you. It can't be much more than an hour's work to replace the motor. Regardless, that's too much money to charge for a repair.
If I were you my next call would be to Ego Customer Service and see what they can do for you. That repair estimate sounds like highway robbery to me.