Large Accountant errors over multiple years

After strongly understanding our taxes this year, I’ve discovered that our accountant has exhibited extreme incompetence over at least three years of our tax returns.

Ranging from clerical errors on our 8606, inability to input 1099-R correctly, to tens of thousands of $’s they reported taxable that shouldn’t be taxed (IRA conversions).

Now we have to amend multiple years of returns, and file a 3115 because we asked a question about depreciation value of our home that was never responded to and that value was just used.

How would you handle this from my situation.

Also, we were charged a much bigger fee to file this year.

Hope I follow the rules mods, first time posting here.