Someone tipped me off to Netdata, an open-source monitoring & alerting tool with a cloud option. It’s another way you can monitor your server besides Zabbix, Prometheus/Grafana, SNMP, and others.
I set it up to test. Easy if you are using a DIY build on Debian:
apt install netdata
edit /etc/netdata/netdata.conf and bind to an IP or just bind to localhost if you want to tunnel or proxy
copy the statsd.conf referenced in the article to /etc/asterisk and restart to load the statsd module
(build and then) load the res_chan_stats and res_endpoint_stats modules
copy the asterisk.conf file referenced in the article to /etc/netdata/statsd.d directory