Scaling into Europe is a headache when your site starts cannibalizing itself....

https://mike-wiki.win/index.php/Hreflang_Sitemap_vs._HTML_Head:_Navigating_International_Architecture_at_Scale

Scaling into Europe is a headache when your site starts cannibalizing itself. We’ve all seen the traffic drop after a messy migration, usually because hreflang tags are broken across subdirectories