You are correct for the Federal, but watch out for any state taxes which may not comply. Even if the state (NC in my case) will agree to extend the deadline for filing, they may (will in NC) charge interest for the extra month if you don't pay by the April date. The state might change it's mind, but for now I personally need to go ahead and send my amount due to avoid interest charges. Some days you're the bug and some days you're the windshield.
“The North Carolina Department of Revenue (NCDOR) announced today that it will extend the April 15 tax filing and payment deadline to May 17, 2021, for individual income tax to mirror the announced deadline change from the Internal Revenue Service.”
But, as said, that may not be true for your state.