I created Fedora35 virtual machine to test and finally got it working but I have to say I think the issue was with Fedora 35. I tried F35 before and many things stopped working so I downgraded to F34 again. A bit disappointing to be honest. Anyway, sorry for the rant.
So basically I think Chromium that comes with pppdf is too old for F35. I downloaded and installed manually Chromium-headless but I think you can do sudo dnf install chromium-headless. Then I went to the install folder /usr/lib64/chromium-browser and copied the contents of that folder to /home/USER/local/share/pyppeteer/local-chromium/800217/chrome-linux. Just copy/paste and replace and merge everything. Finally delete the original chrome executable and rename chromium-browser to chrome.
Now pyppdf is working as expected and I can launch the pyppeteer version of Chrome just like the normal browser. One more thing, when I first tried to use pyppdf I did not get the same errors as you, so I hope this solution works for you.