Ram usage in MacBook

In the Memory tab of Activity Monitor, you may see that Cached Files are using a lot of RAM. This is normal – and when you think about it, is a good thing.

Completely unused RAM does not do anything for you. It just sits there.

RAM allocated to Cached Files contains data that the Mac thinks it might need again.

• If applications or the OS need that data again, before they need the RAM, the system might save an expensive trip to a SSD or HDD to get it.
• If RAM is needed first, the system can just dump some cached data to get the RAM.

Figma has a long history of consuming as much RAM as it can. Its specs call for a minimum 4GB RAM, preferably 8GB or more. And the app easily consumes 50% or more of the RAM in the computer.

Why are you worried about RAM use? Why not use all the RAM available? Check RAM pressure:

View memory usage in Activity Monitor on Mac - Apple Support

macOS is designed to use as much RAM as it needs. It's a resource intended to be exploited.

In macbook it takes 4gb ram in browser or native app compated to pc only takes 2gb ram. 

Mac ≠ PC

I don't know what Figma is.