Freeing up Space by Deleting com.apple.mobilesms

I am wanting some clarification, I have iCloud+ and I have confirm that backup is on for messages on my Mac, that said however between the container Com.Apple.Mobilesms and the library attachment, messages takes up 400Gb of my 512 gb on my computer which is absolutely atrocious.

I have been unable to get guidance other than to use the settings app to remove messages but I don't want to delete it everywhere just on my Mac. It doesn't make sense for me to be paying for iCloud storage if iMessage isn't going to be fully backed up to it.