Depends what systems you've got in your homelab, I guess. Are you using vmware with lots of VMs? Or k3s / microk8s / nomad with lots of containers? Do you have a config management tool that lets you deploy monitoring agents consistently and easily with new VMs/containers?

It's been more than a decade since I've run up prtg, but I recall the functionality was pretty basic - it's little wonder it's easy to setup.

I've used each of the four tools you mentioned you tried. Nagios and Zabbix are good, but not well suited for microservices, very host-centric view of the world. Netdata is also host-centric I think. Grafana is just a visualization tool - what were you feeding that with - Zabbix and Nagios? Sounds like you need yourself some opentelemetry (or compatible equivalent).