Malicious traffic from Cloudflare is impacting cert renewals

While I am certainly able to do that, I do not consider it security best practices to deliberately connect to networks that are aggressively attacking me.

You could then use a DNS-01 challenge that resolves outside your network

I am indeed using DNS challenges, but that introduction of additional external networking services only makes trying to work around abusive traffic a bigger mess. I'm hoping to find a solution that involves fewer mediators between me and LE.