It's weird. When working with a Compose app, Android Studio 4.2 Canary 5 exhausts almost all the available physical RAM (8GB) on my (Linux) machine and then it quits after a phase of hanging. Attaching a screenshot.

See how to report an issues with memory: https://developer.android.com/studio/report-bugs#studio-bugs

I am also using linux and i did not noticed a difference to AS 4.0. For me ram usage is around 3-4 GB. You should upgrade you computer to 16 GB Ram. Especially when you also using emulators which also take an additional 4 GB Ram

Right @Timo Drick 8 gb computers don't work well for Android or iOS development anymore.

I think for Compose it is a little bit more than normal because you do have different compiler and kotlin versions for gradle and for Android Studio itself.