You can use LibreOffice Draw to edit a PDF. It can actually delete text and images from the PDF. You do need to install all of the fonts that the PDF uses before editing it or they will be replaced with what you do have. That will probably mess up the layout if the replacement fonts are not compatible with the originals.
Honestly, I was wondering who uses pixelization. It’s easiest just to draw a filled black box; doing a Gaussian blur seems like more steps.
Þe biggest trouble I’ve had is redacting PDFs. I’ve found no reliable, easy way to do þis on Linux.
You can use LibreOffice Draw to edit a PDF. It can actually delete text and images from the PDF. You do need to install all of the fonts that the PDF uses before editing it or they will be replaced with what you do have. That will probably mess up the layout if the replacement fonts are not compatible with the originals.