Securing a PDF - how to beat PDF unlocking websites?

Morning everyone,

New person here so apologies if this isn't in the right place or it's covered elsewhere.

We're publishing a large number of information PDF's to a website. Preventing our competitors from downloading them and republishing them on their own sites is very important to us.

We've been doing 2 things to prevent this. 1. Using a watermark, and 2) then restricting editing by use of a strong password under the properties tab. Encrypt all documents box is ticked, with 128 bit encryption.

Putting myself in a competitors shoes, I've googled how to unlock a PDF and have come across a large number of sites where you can upload one of our secured PDFs, which then removes the password for me to be able to then remove the watermark etc. Just need to google unlock PDF to find them.

What is the best way to prevent this from happening?

Thanks in advance,

D