How to compress or make it single CSS or JS files for better performance

We are exploring nextcloud and it looks good so far. But there are lots of css & js files, which make the loading time slow.

Is there any simple way to join all the js & css files as a single one?

Thank you.

Popping up in my mind - use http2 with H2PushPriority. E.g.:

    Protocols h2 h2c http/1.1

    H2Push on
    H2PushPriority * after
    H2PushPriority text/css before
    H2PushPriority image/jpg after 32
    H2PushPriority image/jpeg after 32
    H2PushPriority image/png after 32
    H2PushPriority application/javascript interleaved