The big competitor to Apple is Samsung, and Samsung devices tend to be just as locked down as Apple devices (though the prevalence of jailbreaks has been higher, and of course you can sideload apps). Those two companies make up over 75% of smartphones in the US, and neither of their next competitors down (OnePlus and Lenovo) are Google.
People talk about Android like it is the "do anything you want device marketed at end users", but it is the "do anything you want operating system marketed at device manufacturers". One of the many things you can do with such a device is lock it down, and that's what companies who make devices that run Android, like quite-notably Samsung, have largely decided to do.
Google's first-party devices are often quite open, and that's cool and all, but they do not have much marketshare because, in the end, they kind of suck with the various limited hardware tradeoffs they make. Users, generally, are unable to provide a very strong purchasing signal
preference on "is an open device" because they are too busy optimizing for having good cameras or screens or whatever it is that they consider the primary point of owning the phone in the first place is.
At the end of the day, Android then become more of a coalition of brands herded by Google--but led by Samsung, whom at least used to make the vast majority of the actual profit, disproportionate even to their marketshare--in attempts to reign them in on what crazy changes they make, but those limitations do not enforce the device to be open... far from it, really! And so we have seen Google also the target of lawsuits for anti-competitive behavior with their store (including by Epic, whose argument almost made more sense against Google than Apple).