Google domains has an ACME DNS API now, it would be nice to add a plugin to the list. I tried it adding manually in /usr/share/proxmox-acme/dnsapi/dns_googledomains.sh but it is not showing up.
https://github.com/CruzMarcio/acme.sh/blob/googledomains_api/dnsapi/dns_googledomains.sh
https://github.com/CruzMarcio/acme.sh/blob/googledomains_api/dnsapi/dns_googledomains.sh