I would say the total effective tax rate for working middle class in America is around 50% with many states/regions being higher. State taxes, federal taxes, property taxes, excise taxes, utility taxes, water taxes, sale taxes, registration and administrative fees, etc...
The complete step-by-step guide to get back to selling today!
Except eBay you can use the LLC and for other Platforms. There is no reason to establish a company just for one account on eBay.
Except if it's a very profitable account, you need many accounts for security reasons and not sell too much from one account.
If you build it step by step and know how to run a business, it is a good way for an international to have a US LLC.