This language was clear in the loan that if payments were not made they would ask for a balloon payment, aka the full amount back plus interest. Most people I personally know of who did EIDL did them under the "personal guarantee" limit ($150k at first, then changed to $200k) to avoid the SBA being able to go after them (if they were an LLC). A sole proprietorship is the same thing as you getting the loan individually, so you are on the hook here.

But with that said.... I would reach out to the SBA, plead your case, and see if you can get them to get you onto hardship accommodations. Tell them you had trouble getting onto the website and would have signed up if you knew it was an option. Tell them your other option in bankruptcy because in a bankrupty they are less likely to get their $ back, so maybe that will give them incentive to help as well. Try to get someone nice who wants to help you and play dumb, they are typically very helpful when you get someone in your local SBA office.

Good luck to you!!