If all you need is to insert an image of your signature onto a PDF, you can use Xournal.[0]

[0] https://en.wikipedia.org/wiki/Xournal

I wish there was a linux app as intuitive as Mac os's stock pdf viewer/editor, it's as good as it gets when it comes to signing and reorganising documents

Preview.app! It’s seriously awesome. It’s the one thing I miss when using a flavour of Linux.

You can fill and sign, but also redact (actually removes vectors under the redaction blob), combine multiple PDFs and rearrange pages. Does everything I would ever want to do with a PDF and it’s hidden inside what most people think is just the image viewer.