To help clarify things, the late filing penalty has nothing to do with the tax liability, and it doesn't matter if you made money or not. The late filing penalty is because you did not file the 1065 tax return by the March 15th deadline.
Personal 1040 tax returns have a filing deadline of Apr 15th (normally) while all other types of tax returns (1056, 1120, 1120-S) have a filing deadline of March 15th.
Now while the IRS did extend the 2020 tax filing deadline for personal 1040 tax returns, they did not extend it for any other type of return. (Unless I missed something in the IRS announcements they post at irs.gov)
