Install server version of mods?

So, I'm trying to install the Betweenlands on my server. I had, and it worked fine, however, the file was a whole 103 MB, the largest mod by far. The Betweenlands has a server version (works exactly the same, but is designed to be used on servers, and is much, much smaller), but I can't seem to find it in the Mods menu. Anyone know how to get it? It's really affecting the performance of the gameplay.

I already have the mod installed, I'm wondering if there's a way to install the server side version instead (it works exactly the same when put on a server, but takes up much less space). If you view the Betweenlands on Curseforge, you'll see there's a file straight up designed to be put on servers, but I can't find it in the Aternos menu anywhere.

Because it's almost 100 MB smaller.

Fair point, I just thought it might affect performance or something, I guess not. Thank you for your time!