You’re right, this tool isn’t designed to address this problem and is ill-suited.
Lemmy should definitely render a static page and then “hydrate” that with JavaScript in the client. This is a common problem with modern js apps. SSR (server side rendering) is the solution but it can be very complex. You really need to build the whole app with SSR in mind, it’s not really something to bolt on as an additional feature at the end.
Amaze!
Well done!