iCloud storing files on HDD

My problem is in two parts:

1) When putting files into my iCloud drive (via the iCloud folder in finder) it leaves a copy of the transfer on my hard drive in a folder called 'iCloud drive' (from my last upload and in total its 140GB). This copy is now taking up a large chunk of my hard drive that i'd like to reclaim.

a) is this space retrievable on my hard drive, and will it affect its storage in iCloud?

b) is there a way or feature that can be selected that will prevent iCloud automatically copying the files to the hard drive?

2) When using the folder in finder it automatically uploads all of the transferred files to the iCloud folder. Can files be added to iCloud only instead of having them retrievable on my Mac?

I have researched this problem a lot, but I can't seem to find a solution. I have removed file storage 'desktop & documents folder' and 'optimise Mac storage' but the folder remains on the hard drive. And non of the communities pages seemed to address the issue. If you can point me in the way of articles, or provide solutions i'd be very grateful.

Thanks!