Sorry to hear about the stolen laptop, that always stings, especially when family pictures and personal stuff are involved. For large amounts of data, you’ll probably want to mix cloud storage with local backups. Services like Google Drive, OneDrive, Dropbox, and iCloud are fine for everyday files, but if you’re talking multiple terabytes, look at options like Backblaze, IDrive, or even Google One’s higher storage plans. They’re designed for bulk storage and still let you download and manage files when needed.
Since you already have external drives, I’d suggest using them alongside a cloud backup so you’ve always got two copies in different places. That way, if one gets lost or stolen, the other is safe.
As for the old HP laptop, a Windows password by itself is not bulletproof. A determined person could get past it with the right tools, but unless there’s sensitive financial or work data on there, most thieves are more interested in wiping and reselling the laptop than digging through files. If you had full-disk encryption turned on (like BitLocker), that would make it far more secure.