What hosting service is best for multi-site WP

Hey all!

I'm looking to start a freelancing gig where I develop, build and manage WP sites for clients. I've got a lot to learn with building and developing sites but for hosting I feel as though I'm getting whiplash from all the love hate relationships people have with hosting services.

My goal is to be able to manage multiple sites under one umbrella, so one service to host all. Where I can easily disengage some sites to the client if they don't want a managed service and just want website building. It needs to support data segregation (for the purpose of data security), I need to be able to host different products on each site. Whats the best service that offers scalability so I'm only paying for what I need, it needs to support multiple dev users. I have a budget that supports most services but would ideally like to opt for a cost effective site that can support high user traffic (high is very vague, but lets say 100k a month) and a service that manages the security of the page (SSL Certificates etc). I currently have my eyes on vultr, but have read some negative reviews there, unsure if these consistent or just an unlucky bunch.

Any assistance would be great, thanks 🙂