Hi @Baptiste_LC
Thanks for sharing all these details! I agree, the app looks relatively slow to load. Since the components are slow to load, I don't know that a custom component loader would help 
Is the starting page particularly large compared to the others? Or, does your app have a lot of globals? Global scoped queries increase the initial load time of all pages in the app, so we recommend moving queries into page scope, if possible.
More generally, a multipage app with a very large total number of plugins (components, queries, etc), spread across many pages, can eventually become slow on initial load (more performance info here). If this happens, it might be worth splitting the multipage app into a couple of smaller multipage apps. The performance of interactions/responsiveness on a given page is independent of the total number of plugins in the app, and only dependent on the plugin count of the page involved.