Oh yes, only the Rada was mentioned in the constitution. The president was mentioned in an ordinary law. As the blog you linked explains:

As discussed elsewhere, the prohibition of wartime elections is established in Ukraine’s statutory law. Ukraine’s Constitution does not explicitly address the issue of wartime elections, except for Article 83(4) that provides for the extension of the Parliament’s powers until the day of the first meeting of the first session of the Verkhovna Rada of Ukraine (the Ukrainian Parliament), elected after the termination of martial law or state of emergency. Nothing similar is made with respect to the president. According to one of the drafters of the Constitution, this special treatment of Parliament was originally aimed to enhance Parliament’s standing in the constellation of powers and prevent possible abuses during wartime or national emergency.

Law of Ukraine “On the Legal Regime of Martial Law” (2015) prohibits the holding of elections during martial law and the Electoral Code of Ukraine (2019) ordains suspension of all elections during such period.