Nooooo... are you kidding? That's exactly what makes every article a piece. It's perfect as it is! Unify the fonts and you get an academic-style journal.
Sorry, that's one thing we probably cannot fix - the whole idea is that the laying out of the articles is done by authors (not us - the publisher) and the authors have (almost) full control over it.
This means that while we can recommend fonts, we can't really enforce them in this model.
I know the idea for the authors to do the layout is at least 'experimental' (that's the word I prefer to use), but it also gives one more space to be creative (and makes it easier for us from a certain perspective too). See also https://pagedout.institute/?page=faq.php#layout
But it's not the case that on every screen you could fill the page to the desired width and still see a sufficient amount of information to make the tedious scrolling worth it.