RAM disk is waste of money literally, useful back in day of operating systems installed on slow HDDs hundred years ago,

why waste 1/4 of an "expensive" RAM, and have it flushed every reboot/shutdown,
when you can get whole SSD with 100x capacity for about same price

besides, all current operating systems (Linux, MacOS, Windows...) do effectively make use of available RAM, dynamically caching things anyway (unless, you're using some weirdly super-cut-down-de-bloated Windows build which is obsessed about low RAM usage, not being able to manage RAM lolz)