subven1

Really depends on how often you need to touch your data. Tape has high upfront cost (4-5k $ for a LTO-9 tape drive + ~3,5 $/TB in tapes) but you don't have to worry about archive space anymore. Otherwise, NAS space (if you selfhost) is ~15 $/TB + a server which would also be slightly above 5k right now to store your 300 TB.

You can import Youtube playlists into Jdownloader and download for example your "Liked Videos". You can also use "Google Takeout" to export all you files, playlists and history to CSV.