International SEO site structure impeding rankings

Hey! We have a domain with the root page `.com` automatically redirecting the user to the relevant country (sorted by a subfolder structure `/us /au /uk` etc). I've gotten help that these automatic redirections are most likely impeding our U.S. homepage rankings, so a change is neccesary. Great, part 1 understood. But, now I'm down the SEO rabbit hole and feeling overwhelmed. What is probably neccesary is a partial migration or full migration to fix these issues, since the US is by far the most important market for the site. The `.com` being a "country selector" was also discussed, but this was ruled out. * If we do a **partial migration** (Move *only* the U.S. homepage from `com/us` to `.com`), will that hamper the rest of the `/us` content from growing in the long term because of a fragmented structure? Or even make that content rank worse long-term? * If we do a **full migration** (Move *all* U.S. content (including hundreds of blog posts and thousands of subpages) from the `/us` subfolder to the root domain. I guess I will see substantial short-term dips (or even long-term??) for well-performing content. But is the long-term upside of unifying all US content under the core domain`site.com` without subfolders for /us worth it? Or could it be worth to do a partial migration at first and then a full migration later? Note: most traffic is coming from US subpages, such as blog posts and other informational content - the site is about 5 years old. It is ranking fairly well (100k+/month) but some important transactional pages have been hovering around page 2 even though efforts have been made to get them to rank higher. \----------------- Has anyone dealt with a large-scale migration in a case like this? How painful was it? For those who’ve done a full migration of a big site, how did you minimize or handle the ranking drops (if any)? Did you see a full recovery, and how long did it take? Sorry for anyone who needs to read this again from another forum. Thanks!