Appflowy has extremely poor performance. Both in terms of loading large files and RAM usage. See my performance comparison of block editors[1]:

I've built a block editor using Qt C++ and QML that is vastly more performant[2].

As you can see, Appflowy probably even has a memory leak, causing the memory to grow indefinitely in my test.

[1] https://imgur.com/ZL5QCS0

[2] https://www.get-plume.com/

Probably the reason why you can't use it on the Web. Makes it not interesting for at least 50 % of the potential userbase.