Depending on the needs of your clients then that could be a simple digitalocean or heroku, but as they grow out and demand additional services will you be able to offer those or will they have to migrate?

On networking, you could set it up for them but would it be opinionated, ie your way only, or provide the flexibility of AWS and azure networking, vpc, gateways, transits and topology flex, and if not the client may feel constrained.

To better help you then I think you should draft up the service you intend to deliver and test if the market wants that, vs competitor offerings vs AWS scale. And I mean lofi don’t build, test the well defined proposition.