The reason why I Never play the sims 4 at all is because you can't create custom worlds, BUT I recently have been seeing some tutorial videos on youtube that lets you clone & customize & even rename the worlds with the use of tons of mods in the sims 4 which is actually quite remarkable

but there's just one thing, I haven't found any mods to RESHAPE a world, as in, a lot of the custom sims 4 worlds i seen people making are still shaped the same way as the worlds they are cloned after, for example, they still have water & rivers running through them. I wanted to just make a flat plain world in the sims 4.

I would imagine that could be possible to mod if you get a 3d model for a flat plane & are able to somehow replace the 3d object of the world it's self in the sims 4 with a flat plain model but exactly how would that be done?

does anyone have any idea how to do something similar to that in the sims 4?

twisted mexis CAW does this (https://twistedmexi.com/Create-A-World/) it is currently in paid alpha as this tool is very complex and very much not done.