It's easy to bypass the centralization. Trade Bitcoin using DEX, hold in non custodial wallet.
The government have no way to eliminate Bitcoin decentralization, it was never under their control, Bitcoiners always have a remedy of controlling their assets.
Governments can be picky, they can keep Bitcoin as a reserve but may not be fully bound to the system, this reason i am afraid for what the government can do if they keep the pace of legalizing and accumulating large portions of Bitcoin as reserves, not just one government becoming whale but sine it has become a new order for countries to adapt.
You're only talking about the usage of Bitcoin, it's correct you can trade without need government intervention. But, most people convert their coins to fiat, which they need a help of banking system. This is where the government can know if you hold Bitcoin or not.
They can track who sent the money to you, they can ask what the way you get that money etc.
It's easy if you only buy and hold Bitcoin, but very difficult when you want to sell it.