I love PDFArranger. It has basic functions such as rotate, add or delete pages and it comes very handy for large documents. Also It is available on Linux, Mac and Windows: https://github.com/pdfarranger/pdfarranger
I have tried to install it on my pi4 as well but it craps out when doing simple stuff... Maybe it's because I have out it behind nginx as a reverse proxy... I'll try again when I have time, because it works very well (when it works).
I use command line tools for this, for most those things pdftk should be enough and it works great -if the command line is too daunting for you, there's PDF chain a graphical front-end for pdftk.
For creating PDFs from images i often use imagemagick.
qpdf is the best CLI tool that I have used to edit the structure of a PDF. I recommend it if you don't require a GUI, and do not need to edit the content.