I wish there was a CA out there that could let you requests new certs more frequently.
Yes there's Let's Encrypt, which is amazing and works great but the ratelimits really kill you if you're not careful. I've had a few issues where I've triggered the LE ratelimit with a production domain and got locked out of making new certs for a whole week. I would gladly pay for an ACME CA which does not enforce these ratelimits.
It might be easier to resell someone else's certificates.