I have a few thoughts about this.
1)Android is a very secure platform. Even malicious apps are very limited in what they can do without asking for permissions. They can mostly do passive stuff (read device info, read clipboard). The rest is social engineering. So comparison with desktop OS like Windows and Linux are a bit misleading.
2)If you consider malicious apps a problem (and this is a philosophy, some would say it’s the user responsibility to vet apps before installing them), then they are better ways to protect users.
One of the way that would keep it relatively open & enanche security is Google designing certified gatekeepers. This would be any app store or platform with a vetting process. This could include F-Droid, Acrescent, Epic Games Store, etc. Those stores could then send to Google a list of their siging keys as well as the App developer keys. Ideally, this list would be regularly updated in a public list, so any ROM can have a list of certified “safe” apps.
Would this restrict user freedom? Definitely. You wouldn’t be able to install your own app, or an app published exclusively on GitHub. Same goes for security critical apps that use a custom F-Droid repo for timely updates.
Still, it would be much better than the current proposal - which would effectively turn Google’s Android into EU builds of iOS