Based on the IRS wording of the extended 10/16/23 deadline, it extends both filing and payment date.  No mention of interest application or relief.... On its face, it would be a mean trick to grant an extension because of a disaster, forgive penalties ...then stick filers with interest because they filed to the extended deadline.

IRS: May 15 tax deadline extended to Oct. 16 for disaster area taxpayers in California, Alabama and ...