If you can actually contact the IRS at all. I called multiple times last year and wasn’t even able to be put on hold, just “sorry we have too many people trying to contact us, try later”. If you do actually get a hold of someone, IRS is helpful but also outdated (I had to sign up for a fax service to send documentation to them).

Apple’s responses often leave a lot to be desired, but at least you can use support forums and emails with a good response rate.

Note that I don’t think this is the fault of the IRS at all - they are woefully underfunded and understaffed.