Adrien The cheaper, the better the chances of success.
This is a race to the bottom and how bad providers die, Don't do this.
Adrien CloudFlare Enterprise has become an imbalanced selling point. Small companies can’t afford it.
Heaps of options, I'm probably in a more unique situation where the underdog provider (Bunny) has more PoP's, Better routing and includes a ton of features for a very fair price that we can provide even more than Cloudflare at times, Find this for your audience.
Adrien If you want to sell performance, you can’t afford it on the cloud. It has to be bare metal.
Heaps of Ryzen based options, Cheaper than enterprise and single thread performance is great - not ideal but a great first step, Hetzner, BuyVM and many more are coming to the market, Here a dedicated core CPU even with virtualization will be better than a cheap VM.
With billing your options are a bit limited, Blesta would be my personal recommendation, easy to build on if you need to and is on par with WHMCS without the huge bill (Free with a BuyVM VPS, or a great yearly fee) and handles all your basiscs like accounts, provisioning and support.
Build a great kbase and provide a great customer experience, In this space if you've thought about it odds are others have, 10 could have failed and 10 could have done well - The main factor is determination, offering a genuinely good service with a good attitude.
There's people there flipping OVH and Hetzner server's and VPS's and still making sales, If you've come this far and put this much effort into it you can probably do well yourself, Don't let the small things limit and discourage you, if it's an issue with something at scale you will solve it when your business is big enough, until then leverage the great and cheap tech like the CDN's we have access to, The software like enhance, blesta and this community who puts in huge efforts to troubleshoot and share knowledge, you got it!