In short, competition needs to be increased (i.e. more platforms). For example, Amazon wouldn't be able to pull so many shenanigans if users could export all shopping data to jet.com and easily shop on multiple platforms.
The other solution is updated regulations that follow in the footsteps of historical frameworks of antitrust in industries like utilities where it's accepted that monopolies are efficient, but strict measures are put in place to limit abusing market power.