Removing mods from modpacks.

So Ive been trying to add modpacks to Aternos and been failing miserably but Ive recently realised that's because the server crashes if you add in client-side mods, except I cant find any way to remove the client-side mods in Aternos, is there a way to remove them and if not do i just have to download every single mod independently?

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You can't remove, or add mods from a modpack.

You will just have to download every single mod independently, although please note that some mods in that modpack may not be on aternos

The thing is I swear the first time the server crashed it gave me the option to remove the mods that weren't working but I decided not to and now I cant find that screen, but I have not found any reference to that screen anywhere so Im not sure if i was just imagining things