decent offline pdf editor for windows that isn't a subscription?

If it's just filling forms, signing or highlighting, Edge's built-in PDF viewer does all of that for free and it's already on Windows. Right click the file > Open with > Edge. Only goes to a proper editor if you need to change the actual text.

PDF-XChange Editor is the one I'd point you at. There's a one-off licence instead of a subscription, and the free version covers annotating, filling forms and adding text - just watermarks the page if you use a paid-only feature, and it tells you before it does. If you mainly need to change the existing text, LibreOffice Draw opens PDFs and lets you edit them for free, though complicated layouts can come out a bit shifted. Check the result before sending it anywhere.