"Does that mean that I wouldn't use 8915-E for 2020 information?"

Consider Tax Year and Disaster Year.

Form 8915-E is for Disaster Year 2020 for filing or amending Tax Year 2020. That is used for one year only.

Form 8915-F, or "forever" form, is for Disaster Years 2020 and later, for filing Tax Years 2021 and later.