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As your own agency told, I too consider that when the hreflang will be implemented, this kind of issues should terminate. Regarding the sitemap error, it was surely something that could be confusing Google about what site to target. However, I see that you have also an .eu domain name... I imagine that that domain is meant for targeting the European market and I suspect that it is in English. If it is so, remember: In countries like Spain, France, Germany, italy... we don't search in Internet using English, but Spanish, French, German, Italian... Therefore, that .eu domain is not going to offer you those results you maybe are looking for; The .eu domain termination is a generic one, and cannot be geotargeted via Google Search Console. This means that - by default - it targets all the world, hence, you probably can see visits from English speaking users in countries like South Africa, UK, IE, Australia, New Zealand or India, where English is the main language or one of the official ones; When it comes to domains like .eu and hreflang, it is always hard to decide how to implement it. In your specific case, as you are targeting UK, US, AU and IE with specific domain names, the ideal would be to implement this hreflang annotation for the .eu (the example is only for the home page): <rel="alternate" href="http://www.domain.eu" hreflang="x-default"><rel="alternate" href="http://www.domain.eu" hreflang="en"><rel="alternate" href="http://www.domain.com" hreflang="en-GB"><rel="alternate" href="http://www.domain.us" hreflang="en-US"><rel="alternate" href="http://www.domain.com.au" hreflang="en-AU"></rel="alternate"></rel="alternate"></rel="alternate"></rel="alternate"></rel="alternate"> With those annotations, you are telling Google to show the .com to users in Great Britain, the .us to users in United States, the .au to Australian ones and the .eu to all the other users using English in any other country. That will mean that your .eu site surely will target also users in others European countries, both using english when searching (hreflang="en") and other languages (hreflang="x-default"). 2 notes about the hreflang="x-default": People living in the UK and searching in Spanish will see the .eu domain name, because it is the default domain name for searches in every language but English in GB, IE, AU and US; Again, even if you pretend the .eu domain to target only European countries, that is impossible, because the .eu termination doesn't have any geotargeting power (and regions like Europe or Asia cannot be geotargeted via GSC). So it will be normal to see visit also from countries in others continents.

Google Analytics and a noindex tag are completely separate entities. So by applying a noindex tag to your search pages (which is a great idea, imo, reduces duplicate content), you still have the Google Analytic code on the page, which allows it to report to the server and then you can view your data. So yes, you will still get accurate info and metrics.

Thank you Keri! Much appreciated.

I would make a very small mobile site (even if it is a single page) because there is thought that Google is liking mobile sites - particularly of local searches.