But the alternative is another monopolistic tech giant. There is no viable third platform. So I agree with OP, the answer is breaking them up.
> There is no viable third platform.
There is no "viable third platform" because people don't vote against the two existing ones with their wallets.
Can you name an example where a government succeeded in breaking up a monopoly, and the result was better for consumers? AT&T, IBM, and Microsoft were all "broken up", but it didn't make a difference for consumers. In every case, a competitor forced them to change their ways.
Pixel phones have an unlocked bootloader. One can load GrapheneOS onto those phones without needing to jailbreak them.
Even without flashing a new OS, one can install third party app stores (e.g. F-Droid) with open source apps and/or side-load modified versions of those apps.