If you don't want to use HashRouter AND (importantly) you don't have dynamic routes (e.g. example.com/user/{userId}) then you can manually add a copy of index.html for each route route.

For example, if you have /pricing and /login routes, you can make a copies of index.html, one named pricing.html and the other named login.html. The browser should look for the correct file when going to /pricing etc.

You can still use dynamic routing, but you have to use query params like youtube e.g. youtube.com/?v=VIDEO_ID