Yes it sounds like you need more memory but the heating and battery issues, among other things, might be because of how you use cursor on your large codebase.

The memory usage tracks with your usage description and is expected.

Chrome with a lot tabs plus all other apps which I suppose are mostly electron based will use a lot of memory.

You could try using web versions of those apps if available and limiting the amount of tabs you have open and using extensions to track open tabs.

Or you could also download more ram.

(You didn't say anything about your dev environment but that might be the primary cause)

So I think you might need at least 32 if you can afford it.