I assume that the IRS letter you got is 6174, and not 6174-A.
If you correctly reported all of your crypto sales or exchanges you don't have to do anything. As it says in the letter, "You do not need to respond to this letter."
If you have questions, I don't think there's any harm in calling the IRS hotline number at the top of the letter if it will make you feel more comfortable, but there is certainly no need to call.
You can contact Audit Defense for any IRS letter. It does not have to be an actual audit. But I don't think there is any need to contact them. There is probably nothing they can do for you, since there is nothing that needs to be done
I don't think you will get any useful help from Intuit. They will just refer you to the IRS.
