Yes.

They have both. I use the standalone application since it covers everything running on your system and not just your browser.

I use AdGuard to great effect on my iOS devices.

It was the company’s official stance per their official social media account. Not just the CEO/one board member.

I largely agree with what you’re saying, except the official Proton Mastadon account doubled down on that personal opinion. That seems pretty clear that it’s endorsed not just by that one individual on the board.