Whether you can use a recording of a previous years lecture will often depend on how you structure your course and its learning outcomes.
In my subject, the traditional model is along the lines of two hours of seminars for every one hour lecture. Particularly for intro courses, the one hour lecture is the information-giving part of the course, it is not designed to be interactive or discursive, it gives the students the theories, concepts, formulas, data and other information that they must know as the basis for everything else that they do.
They then use the information from the lecture as the basis for discussion, development, application and questions in the 2 hours of seminars.
If a recorded lecture is reasonably good quality and the information you need to disseminate to the students remains the same, then it's not the worst thing to use something that has been recorded before. It is the seminars that require the greatest reworking for online learning.
I haven't reused my lectures, but this is mainly because the sound quality from our in-theatre lecture capture system is so poor. In terms of meeting the learning objectives of the course and ensuring the students learn what they need to learn, it makes little difference whether it is delivered live in person, live online, pre-recorded during the pandemic, or pre-recorded last year.
Given that our teaching hours have tripled during the pandemic due to delivering socially-distanced in person seminars alongside online seminars for those who can't or won't attend in person, and that the university asks us not to deliver any lectures live online because the IT infrastructure cannot cope, I wouldn't fault someone who looked at a recording of a lecture they delivered before the pandemic and decided it was good enough quality to re-use.