I don't see you ever getting a Let's Encrypt certificate. Only ones from Amazon or Sectigo
Your previous thread (see here) I described the changes you need to make to your CAA records to allow Let's Encrypt to issue a cert. That doesn't affect the error you describe in this thread but it will be a problem if you want a Let's Encrypt cert. Do you?
This thread's problem to the Let's Encrypt staging system is related to your DNS servers. Some of them do not reply properly. That is difficult to test with dig commands but see DNSViz Errors for detailed errors.