I found ABViewer (
https://cadsofttools.com/products/abviewer/) a few years ago and popped for the perpetual license. It's fairly fast in the conversion, and if the PDF was generated by a CAD program it's very good in the translation; I haven't had too much luck with text but it may be a difference between SHX and TrueType. It's definitely been worth the investment to have on my desktop and not have to worry about an internet connection.
Highest Regards,
Alan T. Hendry, RA
Intel i7-12700F (2.10 GHz) Desktop, 16GB RAM, 1TB SSD, Win 11 Home 64-bit, DC 23 w/ latest beta
Intel i7-10750H (2.6GHz) Laptop, 16GB RAM, 1.5TB HD, Win 11 Home 64-Bit, w/ DC 22, 23 & latest beta