I rely a lot on customers making changes and producing pdfs the same way they did the first time, e.g. colour settings and geometry and offsets, I am replacing the pdfs in Prinergy or switching in Acrobat.
If i'm making changes I'm using Pitstop and not changing anything I shouldn't.
The danger here is that the designer or print handler opens the pdf and makes the changes, spits out a new pdf with the geometry all messed, not to mention conversion problems away from the edit, colour and font changes etc.
On screen everything looks visually the same in the edit area but explaining Trim Box problems is not going to be fun
I have never had anyone come in with files made from any of Affinity software. I have recommended it to some people who seem to do all their work in powerpoint as a cheap and vastly superior alternative and no subscription.