Message Attachments Taking Up Tons of Space on Mac Despite Messages Being in iCloud

On my Macbook Air, messages are taking up 53.49 GB of storage. From my iPhone, I have all messages stored in iCloud, so I am unsure why they are taking up so much space on my computer.

I have since turned off and unsynced my Macbook from messages and iCloud messages, but the storage is still being taken up. If I delete the Attachments folder from /Users/[me]/Library/Messages/, will it delete those messages from iCloud as well, or just merely from my Macbook. I want to make sure those attachments remain in iCloud.

Any help is appreciated. Thanks.