There’s a grim, apologetic vibe to these messages — I’m sorry I’m taking time for myself but I’ll try to check in on occasion! They’re a vivid reflection of a work culture that valorizes constant productivity and the near-total overlap of work and life. But they’re also do a terrible job of what they’re intended to do, e.g., set realistic expectations for both sender and recipient. A vague OOO message traps both parties in an uncomfortable liminal space where both productivity and rest go to die. The original sender is left unsure if they’ll be getting a timely response or a whether the email will go ignored for a time or forever. The original recipient has taken what is a rock solid excuse (time off) and cheapened it, offering a backdoor for email guilt to creep in.
I didn’t actually put that in my maternity leave out-of-office, but it is what I did when I got back.

I appreciate your email. Currently, I am out of the office but will return after (Date of Return). My access to email will be limited during this period of time.
One year my organization mistakenly left me off the phone directory. I made no attempt to correct that. The only people who could call me we’re those who knew my number; everyone else had to use email.