I’d just stick with “I will be OOO without access to phone or email from XX/YY to XX/YY, returning on XX/YY.” And then whatever directions for directing to your support/backup while you are out. I find that specifically saying ‘without access to phone or email’ sets a good expectation of non-response.
Is your email urgent? If so, you should probably call [Name] at [phone number], and they will assist you. They aren’t in the sunshine – they’re still at work.

We have people who do this whenever they are teleworking, regardless of the circumstances. Teleworking is working and by putting OOM’s on, you are signaling that perhaps you are NOT, in fact, working. Stop it!
I wrote the above comment off the top of my head. I wish I had time to rewrite and edit it. I would have changed “their goldfish” to “a spider they accidentally stepped on”, and would have added more detail to the story of the sister’s death (e.g. “her Pomeranian yapping” rather than the less descriptive “her dog barking”). Unfortunately, I could not do the thorough writing job required for that comment because someone close to me recently … – The person whose out of office advertised his gig on the weekend, for anyone in travelling to [city] – The people in a certain department who have taken to saying things like “if you really need to contact me, call 000-YYY-XXXX where Y is the square root of [insert numbers] and X is the year plutonium was discovered.” – The ones where people have an auto response saying they only check their emails once a day between 1-2pm – “I’m on research leave and I may be slow to reply.” (Whereby it is guaranteed they will reply immediately, because academics do not *really* take breaks).