I swear all of this was predicted to happen by open source advocates of the 80s and they'd be called alarmists/whatever and then 30 years later you had Snowden leaks and all the surveillance bills and now Microsoft, Google, and Apple are all advertisement companies mining data through the software and devices they sell
The best people can do is just keep using and advocating for Linux adoption. Try out degoogled Android or a more traditional Linux phone device. Need more users and funding to get the software kinks worked out. They're not as good as the high end Android and Apple stuff, but it's a process