Earlier quoted context omitted.
Trying my best not to sound like a raving Linux zealot, but what you see as normal productivity stuff I may not have done... ever. Converting a PDF to a png? Why? Maybe IrfanView could do that, it's what I've been using on Windows for any conversion since ACDSee went out of fashion... I've never seen a GUI tool that works as flawlessly as pdftk. Yes, it's CLI, but it works better than anything I ever encountered. Scr…
Have you never needed to annotate/sign a PDF? On Mac OS just open Preview (the sane default for PDFs), use the annotate tools. There's even a built-in UI for "scanning" a signature via the front-facing camera, the software automatically cuts out the background so you have a signature to drop on the page. Save and the PDF is signed. Trying to do this on Linux requires moving a mountain.
I'm not saying you're wrong, but maybe all the office work I've done in my life is simply different.