Thank you friends for the tips. I would do the migration on two steps
1. Get some okay 2TB external SSD and download everything from Google to it.
2. Setup a local NAS (mostly Synology RAID 5) https://www.synology.com/en-me/support/RAID_calculator
I would use some cloud to backup important encrypted stuff.
yeah, i will just say you want at least 3 such SSDs to be sure of the security of the data
i have 3 1tb devices and one of them has a habit of failing when i do a big extended write to it, and it has decent cooling and all, but it's not sufficient, obviously
the failure mode of SSD devices is they stop being able to write, generally they retain the data, even when this happens, but it's important to understand... the other thing is that such archival devices you should keep them inside shielded containers, ideally relatively thick metal containers, tin is a good metal for this, as it blocks X- and Gamma rays well which are the main way you get data corruption on these devices (this type of radiation also impacts RAM btw, which is what the whole point of ECC memory is, and similar things like this (the memory devices also use some form of forward error correction to protect against this as well, i forget the names of them, they are used on magnetic spinning discs as well)
