Why do I have to keep downloading same files from iCloud over and over?

I have a 1TB MacBook pro max that I use for home and office.

I have some folders and documents of around 400GB that i want to keep on the local drive to have the flexibility to look at and use whenever needed, but still I want these to remain on the iCloud to be backed up and to allow me view it from my iPad or iPhone.

unfortunately I would have to redownload these folders and files almost every day which is becoming quite annoying and time consuming.

I have "Optimise Mac Storage" checked to keep all files on the cloud and want to have the said 400GB to be available locally too .

Am I missing something here?