But would I trust you with my financial paperwork if you missed that I already answered this question?

You haven't answered that in your question. You didn't say why the bureaucracy is a problem and why paying someone to deal with it isn't a solution.

Edit: oh I see the answer nested in a reply near the bottom. Probably worth including it in your original question.

I've also noticed a disturbing trend with pseudo on-call availability, even on the weekends, labelled as "flexible working hours".

Then there's always the "unlimited time off, we trust you".

Yes, the company I'm at now has the 'unlimited time off' policy. Which has been shown to reduce the amount of time off people actually take, and means they don't have to pay out vacation when you leave. And that's on top of the perception that they're being kind to their employees. A triple win for the company.

But that's exactly why I want my 80% time to be officially recognized. I don't want to feel guilty or worry that I haven't justified my existence when I'm not there on Fridays. The contractual 3-day weekend means a lot more to me than an extra 20% salary with strings attached.

What happens if you test that unlimited policy and take say every Friday off?

Your coworkers will resent you, and maybe try to get you on the crap projects.

Sure, but if something happens and I can't actually keep making that much money, there's no going back to the initial state.

Where do you live? That really does sound like a beurocratic nightmare.

mentioned in OP: Romania

It's a good idea, if the salary talk is after I've had a chance to prove I have value.

But a lot of times there's actually a specific field in the application form with "expected compensation".

Put market rates down in that field, and then when they reach a hiring decision, say "By the way, because of tax rates in my country, I'd like it if you could make my salary no more than $55K and donate the rest to these charities." I don't know any business that wouldn't be glad to find out, on hiring decision, that their new employee will cost them half as much as they bargained for and they can take a tax write-off on the rest.

If you're trying to get a job at BigCorp that's probably an HR nightmare to figure out.

That is correct, I edited my post for better clarity.