Open Bitcoin Core and set it up as a pruned node, the amount for the blockchain doesn't need to be large, you can stick to the default of 2, 5 or 20GB (forgot what the default is, my nodes aren't pruned). When it start to sync, take your device offline to interrupt blockchain download temporarily.
For multiple pre-2017 wallets, I'd have a different approach: before you take the system offline, download the non-pruned blockchain until early 2018, so you can verify all wallets individually after that. It's "only" 200 GB that way.