Hi, we have multiple SuiteCommerce websites under one account, but on the Item record there’s only a single “Display in Website” checkbox. What’s the best way to control which items appear on which website?Right now, we’re using Commerce Catalogs + disabling “Show Uncategorized Items” to manage this — just wondering if there are any alternative or better ways to do this? Appreciate any suggestions!

That's generally the best way to do it. Categorisation is generally the best way to do it on a per-site basis. For a per-customer basis, it is Personalized Catalog Views.