Lightweight metrics options for k3s/Pi cluster

What are my best options for metrics on a k3s/Pi cluster (five, soon to be six, 2GB Pi 4s) that are more lightweight than Prometheus?

(I ask largely because every time I install Prometheus, its memory usage rapidly grows to the point that it’s repeatedly OOM-killed, even on a very lightly-loaded worker node. So, if that’s in any way the general experience, I presume there are some lighter-weight alternatives to be had?)