There is a lot of information regarding digital privacy and security including a lot of misinformation which ignore best practices, promote insecure products or products with no real privacy benefit, and even spread misinformation and conspiracy theories about "big tech". This guide aims to provide real privacy and security.
You should start by creating a threat model. For most people, this would be to protect your passwords and other sensitive information from hackers and malware. Having privacy and security does come at the cost of convenience, so you should balance these two things. Between privacy and security, most people should prioritize the latter over the former because it's impossible to have privacy without security.
Most people need not worry about open source and closed source software. Despite common belief, open source software has no security benefits compared to closed source and is simply just another release model. Lots of proprietary software is actually more secure than their open source counterparts (e.g. Windows and macOS are more secure than Linux, Chrome is more secure than Firefox, Bitlocker is more secure than Veracrypt, and Microsoft Office is more secure than LibreOffice).
Reading Material:
https://privsec.dev/knowledge/threat-modeling/
https://www.privacyguides.org/basics/threat-modeling/
https://www.privacyguides.org/basics/common-threats/
https://seirdy.one/2022/02/02/floss-security.html
