Convert bitcoins into euros, and withdraw them from ATMs
Understand the differences between OAuth 2.0 vs OpenID Connect vs SAML and how it works with concrete examples
Paying on Amazon in cash is possible without fees, by recharging your account with a partner.
Tweak Firefox settings to better privacy in the about:config. settings. Settings to modify, with detailed explanations.
Cryptomator is a free alternative to pCloud Crypto. It is reliable, free, open source, and fully integrated through API to pCloud.
A big step to feel better and to restore your privacy would be to would be to start by deleting your facebook account forever.