Dude. It's one page of plain text. Maybe two pages. It will be transcribed by brute force in less than an hour, if need be. Probably by an unpaid intern.
You either want recruiters to help do all the leg work for you, or you don't. And you either want the job, or you don't.
If they have a policy of lubricating introductions under a branded letterhead, it's gonna go down that way.
The file format protects nothing. And by nothing, I mean absolutely nothing.
It doesn't even change the pace of what happens by slowing things down.
In the past, I've been a hiring manager receiving resumes treated this way by agencies.
They always, always screw them up. The resume is hard to read, formatted incorrectly or whatever. Most of the time, I simply went by the linkedin profile.
I've been in the situation of an interviewer, having to painfully show the skills the recruiter edited into their resume to get them an interview.
I absolutely agree with OP about being worried about edits, except I generally take it to the maximum extreme and don't use dedicated external recruiters at all when looking for work.
If it's encrypted, no one can read it, and thus it cannot be transcribed without a key file.
If a person can read the words, it can be transcribed and reduced to an unformatted string, including an amount of white-space padding.
If the information on your resume cannot survive a reduction to plain text, and still remain relevant, something is wrong, because that's the premise of a resume: to standardize job applicants.
So I converted my full generated resume to PDF into a word document, line by line.
Turns out, it was only so they could slap their info on it, reword my words and produce a PDF.
I asked the employer later, they said they prefer PDF as it's easier to print.......... Snakes. They're leeches in snake skin.