Would there be any performance differences between creating multiple "websites" and a single "store view" for each compared to having 1 "website" with multiple "store views"?
It will depend on how you create your catalog. It could be a good idea to take a look again to https://docs.magento.com/m2/ce/user_guide/stores/websites-stores-views.html
Websites and Store views are supposed to be used for different things.
Maybe one different could be if you use prices at global scope or per website and have different prices per websites for the same product. But without knowing your catalog and configuration is hard to be sure.
(my 2 cents)