Why Open Source?
Open Source means that the code behind each system is available for scrutiny by anyone. This means that it is almost impossible for developers to be doing something nasty with your private data.
Any of the services from Google, Microsoft, Apple etc. use closed systems that are not available to scrutiny for privacy violations. When you use one of these systems you have no idea what the company behind it is doing with your data.
The quality of open source software is superb. Systems like Linux power 40% of the web servers in the world with systems like WIndows only powering 24%.
Open source feature sets get added by user demand and not by the corporate need for new versions. That is why most open source software looks less daunting when it is running. It also means that the software doesn't 'bloat' into a resource hog like most proprietary software. Yes, this means that some of the more esoteric features might be missing, but 99% of users won't notice.
Open source software is normally developed by a dedicated team of enthusiasts who use it themselves daily. More often than not these teams use a Continuous Integration/Continuous Development (CI/CD) which means that features and fixes are being constantly added