Certificates have a static expiry date by design - it's not "LetsEncrypt expiring the cert". There is no way to avoid expiring a cert if the DNS entry is still there - all you can do is make it easier to renew the cert. That means it must be automated, in which case it doesn't matter if you need to re-create a DNS entry.
In my experience, it takes a little effort to set things up the first time, but from then on it just works.
In my experience, it takes a little effort to set things up the first time, but from then on it just works.