Formulars, such as calculating a sum based on the preceding fields.
Field formatting, such as appending .00 to a currency amount
You’re doing it wrong. PDF with embedded javascript is a nightmare and it still doesn’t make PDF equal to excel.
Better generate your documents with your favourite HTML templating engine from your DB and convert them to simple PDF in the last step.
LibreOffice notoriously renders Microsoft Office documents incorrectly in my experience.
Only had that experience with badly designed, macro ridden documents which there’s no excuse for anyway nowadays. I use a lot of print templates (various label printers) and it works flawlessly.
Also, exporting a non MS file format usually imports fine in LibreOffice, even with complex documents.
The ability to quickly edit PDF makes it the office suite of my choice.