For most personal projects, hosting on the cloud may be overkill, but tempting with its supposed ease of use and benefits of scale. Self-hosting is often overlooked as a solution with the benefit of simplicity and cost.
Interesting discussion and demonstration of self hosting the kinds of apps most personal projects will end being.
Given that the domain of the site that you’ve made resolves to a Tailscale relay server IP, I don’t see how the ISP would get alerted. Unless you’re getting huge amounts of ingress traffic to your home IP.