Freeing up phone/iCloud space

Ayyy. Hope y’all are well

I’m wanting to move all my pics/vids off of my phone/iCloud to a plug and play external storage device. Hopefully with the appropriate ports to get them off of the phone and onto a computer in the future.

Does such a storage device exist?! Any recommendations on ones you’ve used?

iPhone 15. No computer. Or banana for scale.

Thanks all