photos and files on icloud

You won't be able to simply "move" these photos to iCloud as you are planning.

iCloud is a syncing service, not off device storage. There is an optimization feature which will reduce the amount of local storage needed, but there will still be some presence of your Photo Library on your Mac.

Should I consider using an NAS drive to build my own cloud or use iCloud for these storage purposes to keep space freed up on my Mac?

Are you using the Photos.app to manage the photos?

Photos cannot work with a Photos Library on a NAS. You cannot use any kind of network share or synced cloud storage for a Photos Library at all (Updating from iPhoto to Photos for macOS - Apple Support):

 If you store your Photos library in a location that's part of a cloud service (for example, Dropbox, Box, or Google Drive), your library might be damaged by the syncing process. As a result, you could lose photos.

To see your photos on all your devices, you can use iCloud Photo Library. To back up your library, you can use Time Machine.

What you could share on a NAS would be folders with photos, but not a Photos Library.

But you can only access a photos library remotely, if you log into the computer, that is hosting the library remotely and run the Photos.app on the host computer. The library needs to be on a locally mounted drive.

And as a further complication - Photos is strictly a single-user application. Only one user at a time can access the library in Photos. Writing to the Photos Library may change the file ownership of internal files. If another user from a different user account tries to open the library afterwards, the other user will need to repair the library to rest the permissions. That is why Apple recommends to enable the "Ignore Ownership" flag for any external drive, that is hosting a Photos Library and may be used from several different machines or user accounts. Clearly you cannot put any private pictures into a library on such a volume, see: Move your Photos library to save space on your Mac - Apple Support

Apple does not currently offer the ability to share an entire photo library via iCloud.

Using Family Sharing you can each access a common album, but not the entire library automatically. In their you could place all photos from the "master" library in to the shared Family Album, but I'm not sure how feasible that would be.

Putting the photos on a NAS should allow everyone on the same network to see them.