Please do. Maybe you‘ll find something useful. I found radicale working best for me (it was easy to install and selfhost). Selfhosting covers many topics, so it‘s difficult to share additional links here. But if you do a websearch, you should find good tutorials. Try to host in the local network first, and install a VPN to access services like CalDAV or CardDAV on the road. This will keep you from spending time on additional security considerations when hosting something on a public accessible host, which can be overwhelming when still being at the beginning.

Do you mean something like CalDAV? There are some solutions listed on the awesome-selfhosted github list