Definitely not a one-size-fits-all choice, but Kubernetes can be so easy and there are so many benefits that get you from one small app to a medium sized business that it seems like a no-brainer for someone starting out. Spinning up k3s is pretty minimal overhead, but right away you can handle storage and backups very easily, automatic certs for all your apps with cert-manager is pretty much a one-and-done, traffic management for external and internal tools is easy, and even logins for websites is just an annotation in a yaml file. You can spin up and try out any software you want without spending time configuring it or setting up additional servers- and when you do need more hardware, it's one command on a virtual server, and just about as easy with physical hardware.

2-3 miniPCs, cloudflare, tailscale, and k3s can save (possibly tens of) thousands on SaaS products, and would probably scale you to a company of dozens AND host your product.