I made a SWAG at my storage needs and I would need 2.204 tb to get all the movies on the drives. So a 4 bay NAS with 10 tb drives would be ideal.
Using RAID10 you would have 20TB available. Seems more than enough.
The last versions of the ****play models from Synology decode natively H.265 format, and support 4k streaming - that means able to transcode several simultaneous streams at lower resolutions. Could be an option for a future-proof setup.
This one, for instance: https://www.synology...ducts/DS418play
DS918+ could be another option.