See, in my head, “as soon as possible” reads simply as a more formal way of saying “I will respond at my earliest convenience.” Like, either way, this person is getting back to you as soon as they can, whatever that actually means.
I worked for a federal contractor back during the Great Recession when government offices were shut down/working with a skeleton crew. I still remember getting OOOs from almost every email address in the agency we worked at explaining they were on furlough & to contact one specific person if the issue was urgent. We all assumed this poor person was hiding under her desk, rocking back & forth, with her head in her hands.

If you have a corporate email account at work, the chances are you'll also have some kind of setting that enables you to tell people when you're on holiday or out on the office on business. But what if you don't? Or just want to set up an email auto reply on your Mac at home?
To remind us – as if we needed reminding, as we vainly strive for ‘inbox zero’ – of just what a time drain email has become, Kay Woodward, UK-based author of What Would She Do?, has wryly channelled one of her book’s real-life heroines, Emmeline Pankhurst (and Pankhurst’s movement’s motto) in her OOO. “Deeds, not emails. That’s what the Suffragettes need. And let’s face it, I’m probably in prison anyway, so couldn’t reply even if I wanted to.”