Welcome to the Q&A Forum

Should I remove the og:locale in Yoast that for some reason references 'en_US'. I'm using Wordpres multisite so I think it pulls the default language  in the plugin even though 'en_AU' is in the head of the AU site.

I've set up a dummy domain (Not SEO'd I know) in order to get some input on if I'm doing this correctly.

Here's my option on the set up and https://technicalseo.com/seo-tools/hreflang/ is saying it's all good. I'm self-referencing, there's a canonical, and there is return tags.

https://topskiphire.com - US & International English Speaking Version

https://topskiphire.com/au/ - English language in Australia

The Australian version is on a subdirectory. We want it this way so we get full value of our domain and so we can expand into other countries eventually e.g. UK.

Q1. Should I be self-referencing or should I have only a canonical for US site?

Q2. Should I be using x-default if we're only in the English language?

Q3. We previously failed when we had errors come back saying 'return tags not found' on a separate site even though the tags were on both sites. Was this because our previous site was only new and Google didn't rank it as often as our main domain.

What is your domain authority, age and indexed page number?

If you've come to the point where you've tried every possible e.g. cleared all crawl errors, disavowed and removed 7/10 links on the spam score link scale in OSE. Remove pages that Google may perceive as invaluable. Then and only then would I go to a completely new domain.

I wouldn't use any content from the previous site either as your original site would most likely be given credit for the original source since it's in Google's index already.

As you can tell it would be a last resort for me to move domains unless I had very few indexed pages / valuable inbound links and a low domain authority I could easily build up again.

Are you moving domains just because you've been hit with an algorithmic or manual action?

I'd personally try and solve the penalties before I'd make the decision to move to a new domain. If you don't want to solve the penalisation issues on your current site and move directly to a new one I'd try and distance myself from the old domain and establish no connection between the two sites.

If you feel your old domain has a high authority and you desperately want to keep the value you have built up then it's quite simple. You need to solve those penalisation issues. Work with the Google Manual action team to disavow spammy or illegitimate links. Focus on only keeping unique and engaging content on your site and adhere to Google Panda's solution criteria - duplicate content, titles, descriptions etc. Use Screaming Frog or Moz Pro to detect these issues.

Focus on helping the user while not breaking Google terms and conditions and you'll be fine.

One last note. A client of mine was hit with a manual action and I believe algorithmic penalisation. His site was able to recover in three months with a lot of work. The back and forth between Google's Manual Action team was the most time consuming.

There could be variety of reasons for the loss in rankings. It depends on changes you've made on your website or marketing strategy. What type of strategy have you in place?

There could be variety of reasons for the loss in rankings. It depends on changes you've made on your website or marketing strategy. What type of strategy have you in place?

What is your domain authority, age and indexed page number?

If you've come to the point where you've tried every possible e.g. cleared all crawl errors, disavowed and removed 7/10 links on the spam score link scale in OSE. Remove pages that Google may perceive as invaluable. Then and only then would I go to a completely new domain.

I wouldn't use any content from the previous site either as your original site would most likely be given credit for the original source since it's in Google's index already.

As you can tell it would be a last resort for me to move domains unless I had very few indexed pages / valuable inbound links and a low domain authority I could easily build up again.