It won't be that dangerous, no need to worry. In the worst case scenario they'll tell you some number and you'll pay it back over time. The IRS wants to get paid more than they want to emiserate.

Also I know how anxiety and avoidance (and other things) can make things like this happen. It's pretty common as a category of thing that people do. The dumb thing in this situation is a tax system that already knows what you owe but makes you actively jump through hoops to pay taxes just so some tax prep companies can collect rent off of workers.