Sounds like it could very well be a mod doing something it shouldn't. Try disabling all you don't need, or use the -noWorkshop or -disableMods launch option to easily disable either all workshop content or just mods, if you don't need any.
Originally posted by BoerenkoolViool: Thank you for your response! The mod says it took up 19.4GB of RAM.
and will it help if I download the missing assets or not?
Thanks!
Downloading more assets will increase memory usage. Everything you're subscribed to takes up a bit of RAM. So the less you're subscribed to, the less RAM is used.