Here is the latest version of flaresolverr with this fix implemented: https://github.com/digitalnomad91/FlareSolverr-udetect-patch/
Note: I haven't tested running it through a new docker image / container, but it should work just fine. I'll include a systemd service implementation for those that want to run it standalone.
Original issue that started several weeks ago: FlareSolverr/FlareSolverr#811
Still waiting on this (seemingly) more robust method to be implemented & released: ultrafunkamsterdam/undetected-chromedriver#1420
I also put together a small browser extension that can run in Chrome or Firefox that worked well enough to get me through the periods where CF was winning. Will probably be useful for if/when there are no known solutions like right now: https://github.com/digitalnomad91/cloudflare-bypass-extension
Note: Don't forget to pip3 install the packages imported below & then you can run python3 fuck_cloudflare.py and check if it is working.