Maybe we have to start accepting the reality that we are almost losing the anonymity feature we have and it is probably lost it totally in the future.
What are you talking about? Let me give you an example in the case of the Netherlands:
You can buy Bitcoin without exchanges, p2p or on a decentralized non-KYC exchange like
https://bisq.network/.
You never have to give anyone your public keys, so you're absolutely anonymous when purchasing through Bitcoin.
To avoid tax evasion, you declare that you hold e.g. 20,000€ in Bitcoin end of year, and pay your wealth tax, but nobody still knows which address belongs to you. You can receive Bitcoin, send it, all without anyone knowing who these addresses belong to.
As Bitcoin's value increases and maybe you also accumulate more, you just declare the new value of your holdings at the end of the next year etc.
When your holdings will reach e.g. 20 million € in 20 years (exemplary numbers), you will have a 'paper trail' showing that you accumulated year after year + your holdings increased together with Bitcoin's value increase, so nobody will question where suddenly those 20 million € come from.
You were simultaneously anonymous AND complied with all laws and paid your taxes, which means you'll be able to 'cash out' those non-KYC coins in the far future without issues.
It's not so hard!
PS: If your goal is to evade taxes using Bitcoin and it doesn't work out due to different reasons, it's not Bitcoin's fault, it's your fault
because you shouldn't do that in general