I'm completely OTel with Prometheus, Jaeger, and Loki now. No reason to fart around with dated collection/analysis tools with data silos -- OTel is good enough for work, it's good enough for the lab. I say this as someone who used Nagios and MRTG for many years, and have contributed to Nagios Core.
I'm pretty comfortable working with Ansible and Chef, though everything except the network equipment in my lab runs on k8s and Talos now. I've managed fairly complex Prometheus and Nagios configs with Chef and Ansible in the past -- not too tricky once you have a config management tool on your belt IMO.