What is it that bottlenecks it? CPU grunt/GPU/RAM?
To be honest, even 64GB isnt completely rediculous, I have had a city hit nearly 30gb so I am not sure how much of the rest of your system is using at the same time.
You need 32gb ram and really really fast cores for this game, but to be fair the game engine probably needs optimisation,
No idea about mods for the game but I guess if they don't work in the EGS then the Steam version is only £3.49 on CDkeys.
Do you think it's worth the mods?
Steam version has also been in the 99p tier of Humble Bundle several times with a bunch of the DLCs so keep an eye on Humble Store, Humble Monthly etc.
Sure is generous of Epic to give away such massively valuable games though
Without mods you are not even going near the capabilities of the game or what you can achieve with it.