The problem here is that the people who announced the "open" platform option were lying to everyone in order to gain market share.
You can still lament the wider societal scale impacts of increasing controls. If both Google and Apple become walled gardens, then what exactly is left? And people need smartphones to get through daily life, interact with banks and government offices.
And I bet Windows is going to head down the same path. ID-verified-by-default, only government and corporate-approved apps installable, AI surveillance running in the background analyzing your every click (for your safety) etc. You see, we need that to catch the bad guys.
The solution is to force Google to keep the promise that they made to consumers, which is the job of the courts.
I would expect them to lose yet another antitrust case over this if they don't back down.
Does Google want to have Android and Chrome stripped from their control?
That would be amazing but it's not going to happen.
And the EU will back their sideloading validation because they want to spy on all of us anyway. This will be done with a backdoor in each chat app, meaning they want to be able to block unsanctioned apps.
Apple didn't invent walled gardens, and walled gardens are not illegal unless you do what the EU did and change the law.
What is going to bite Google on the ass here is selling users an "open" platform and then using anticompetitive tactics to yank those supposed freedoms away.
Look at Microsoft's Xbox platform. It was created, advertised and sold to the public as a walled garden with no legal repercussions at all, because walled gardens are not illegal.
On the other hand, Microsoft created Windows as an open platform and sold it to the public as such. When Microsoft tried to use anticompetitive tactics to maintain control of the platform they sold as "open", they were found guilty of antitrust in jurisdictions around the world.
Google made the choice to sell Android as open. "Sideloading" apps was the only way to install apps at all for the first couple of years. The decision to sell Android as "open" only to yank those freedoms away will have legal consequences again here.