I checked a bit so far ( did not play but looking over code).

To solve some problems a app could be a good solution for speed on phones. For Computers is the question if it could work already by minify code via cloudflare to a decent speed? IDK on some websites it works from "unuseable" to "useable", will not solve the core but from here it could be useable and become better afer ( useable in terms of load time).

I expect ( did not look) on card mechanics. Those could be maybe better structured for less need to load all ( maybe already implemented).

Pictures have a lot of potential always to reduce load times too ( easy to solve with many different sizes and downscaling).

Was only a 10 min look. So some stuff could be wrong i did write above.