I’ve done the on prem design. I’ve migrated people entirely to the cloud. I specialize a little in between.

Without any shred of doubt the cloud is going to be more cost effective than self hosting for 99% of all use cases. They’re priced that way intentionally. You cannot compete with Cloudflare/AWS/GCP/Vultr/Akami/Digital Ocean/etc.

My homelab isn’t about scaling, production workloads and definitely isn’t accessible to anyone but me. I’d argue using it in any other way defeats the purpose and shows a lack of understanding.

That’s not the point. Its unprofessional. Someone is going to smash and grab OPs idea and actually have the skills to host it properly. Probably at a fraction of the cost because OP doesn’t understand that hosting SaaS products out of his house isn’t professional or effective.

Also; cloud is cheaper than self hosting at any small amount of scale. This wouldn’t cost much to run in AWS if built properly. The people who struggle with AWS costs are not professionals and have no business hosting anything.

SLAs?

You’re going to need a redundant ISP and a generator. You’ve left the territory where it’s economical to self host something if that’s what you’re looking at. You still have several other single points of failure.

And I’ll be honest, your setup isn’t ready for an SLA either. Just having a second machine is such a small part of what you need to do before doing any guarantees. Are you using a Dynamic DNS service? What’s the networking setup look like? Router to Compute?

From the sounds of it, you’re not a professional. It might be time to engage an expert if you want to grow this.