Use client-side-encrypted online storage (any one of the many AWS-based choices, say). Unless someone already had passive/active access to your machine before

Use client-side-encrypted online storage (any one of the many AWS-based choices, say). Unless someone already had passive/active access to your machine before you left, they won't be able to get at your data. Your restore should be fine, too. Just watch out for passive access being added by the tech teams inspecting your machine (say reinstall-persistent malware) - though this shouldn't happen in the majority of cases, we'd hope.