I wouldn’t know about market share, but why would market share be a disqualifier to your statement? GrapheneOS and LineageOS are both massive projects with a lot of users. It should be mentioned for those that might be interested to know that they have an option for privacy. Not saying you were doing this, but I hate the defeatist attitude that everything tracks so why try? It’s wrong.

I use LineageOS and Linux and FOSS apps/software and selfhost services… if it’s something you care about, you can regain control and privacy over your data.