I use it for Home Assistant and ntfy in combination with Caddy. Certificates are managed by Vaultls (https://github.com/7ritn/VaulTLS) which makes it quite easy to setup and use on new devices.
I can confirm that the resource usage is quite low indeed. I only used it with Nomad instead of Kubernetes, so I can’t comment on how to best migrate PVs and PVCs.
I’m currently using Piraeus / LINSTOR and am quite happy with it: https://github.com/piraeusdatastore/piraeus