For small edits I usually use https://xournalpp.github.io/
I think OnlyOffice also recently added PDF editing.
I second xournalpp. I used the older xournal to get through university.
Also, if you only have to add some text or images you can use firefox.
Stirling-PDF is amazing
Oh wow how have I not heard of this before?! It looks incredible
Yes! You can easily host it yourself in Docker, Podman or even native.
Do you mean "Based" OS or based os?
It's very limited, but you can use Gimp or Inkscape to edit a pdf in a pinch. IIRC gimp can't edit existing text in pdf, but inkscape can.
I used Inkscape a lot on PDFs with forms and broken layout. The beauty of it, you can fix other problems, too, use your own font or change the font of existing text. (:
This is an intuitive PDF page editor for linux: Pdfmixtool
LibreOffice Draw can make changes to PDFs.
having layering(hope that the right word for a group of text, icons and symbols) issue where icons and symbols go missing or get replaced by square boxes
Might be an issue with fonts?
Some pdf are optimized to hell to the point of unused glyphs got removed from the embedded fonts to save spaces. When you edit them, some characters you added won't be rendered if it's missing the glyphs.
Try to make sure you have all of the fonts used by the PDF installed on your system. I tend to only make small changes, but not having the correct fonts causes issues for me.
If you don’t mind the learning curve, Scribus does a good job.
