Assuming you are already using the
latest test version, I am not aware of anything else I can do to FFF to help with further CloudFlare issues.
I could ask the usual questions and make the usual recommendations about "don't download too much, too fast, give it a few days" -- especially since we don't know what limits may apply now.
I was able to download 8 books totaling 82 chapters this afternoon(plus 6 'already downloaded'), but that's the hardest I've tried to push it since adding cloudscraper.
Some people have reported success with VPNs and switching IPs.