Oh yes, Google and also MS are the biggest distributers and developers of OpenSource, it's true, but also for own advantages with inbuild tracking and profiling APIs, best example Chromium or Android as is, full FOSS, but a lot of work for companies and devs which want to use it, to kick out all the Google tracking crap it has by default.

To be clear, OpenSource is great for develope and distribute software, but it's a big mistake to think that FOSS is synonym of privacy and security, this depends only on the author and what he pretend with it, very debatable in case of big corps like Google, MS, Amazon and Facebook. That they sponser other OpenSource projects means nothing, when they can use it by themselfs (apart of the sign in with Google option which some show) or maybe obtain the pemission to include their APIs, apart of tax advantages.

For sure are tecnically high quality products, but there are alternatives with equal quality by start-ups and some devs, without all the spyware from big brothers, they always preferable. FOSS also has a lot of different licenses, which is mandatory to read to know what is allowed to do with it and what not, not always so open. The only real free license is this one.

In software it's always mandatory to read TOS and PP, if it has a good support and community, if it has a good maintance with regular updates, if it don't track you or sell your data to third party as business model. Irrelevant if it is FOSS or not.