Ugh......don't know why this isn't more obvious in the help docs....but I found it online after 20 mins of futzing around trying different combinations.
When you register a domain with google domains you can set up to 100 sub-domain forwarding etc eg
The problem I was finding is if I typed in www.Acme.com it was forwarding fine. However, if I typed in http://Acme.com it wasn't working at all.
Basically would return no such domain....... (even though I had already setup the *.Acme.com wildcard to work - and it was working fine, eg if I typed in random subdomains that didn't exist.....would send them to www.Acme.com just fine).
What I was missing is forwarding "the google naked domain" and how you do that is setup subdomain forward as you always would......but then enter just @ on its own in the subdomain then fill out www.Acme.com as the destination.
Ugh like I said.....simple but lots of futzing around to get there.
Hopefully through SEO this post will help someone out :)