What should you do?
In all events, if you find yourself living and working in the US during COVID-19, you should retain contemporaneous documentation to prove the period chosen as the COVID-19 emergency period, and that the relevant business activities conducted would not have been undertaken in the US, but for COVID-19 emergency travel disruption.
So, in short, don’t lose your passport with your original entry/exit dates, flight records, and anything else that proves your stay in the US was extended due to the impact of COVID-19 on your travel plans, and be ready to provide them to the IRS if asked to.
As a nonresident alien or foreign corporations (including those that are partners in partnerships) you can submit protective filings of your annual US tax returns, even if you believe you are not required to file for the 2020 taxable year, because you were not engaged in a US trade or business. This would allow you to avail yourself of the benefits and protections that arise from such filings, such as those relating to deductions, statutes of limitations, and claiming tax treaty-based relief.