I get what you’re trying to do, but the issue isn’t really where your followers are from—it’s how you’re targeting and positioning your content. Follow/unfollow tends to bring in a very mixed, low-intent audience, so you end up attracting whoever happens to be active rather than people who actually fit your ideal market.
If you want more US-based followers, you need to be more intentional. Focus on engaging with creators and communities that already have a strong US audience in your niche. Comment on their posts, join conversations, and create content that speaks directly to problems or goals that resonate with a US audience. Even small things like posting at US peak times, using culturally relevant examples, and writing in a tone that matches that audience can make a difference.
Also, instead of chasing volume, it helps to think about quality. A smaller audience that actually relates to your message and has buying intent is way more valuable than a large, random following. Over time, your engagement patterns and content will “train” the algorithm to show your profile to more of the right people, but it takes some consistency to shift that.