How to Integrate Custom Elements in a Web Application

Each team can upgrade their own react separately. We usually go with a runtime approach so if let's say we are building fully client side render page and the mechanism we use for doing the integration is wrapping the applications in custom elements. If you do a server side render when that application this would look different because then custom elements can't be used. You even want to build a universal application which renders on the server and on the client then you also need another solution. So how does that work then when you have completely different frameworks? Is it just a matter of they go through individual build processes and then the final artifacts are what is combined on the page?