Just one thing that confuses us, when the bitcoins we own are legal asset then why should we cover them up from the government?
It is like you telling someone a secret, if the secret has gone more than 100 miles should not be surprising, ones you reveal an information to the government, also know that you are revealing it to scammers. The data breach on exchanges and other centralized services is enough to answer this. Ledger is a reputed hardware company and yet not still an exchange, why are people even calling ledger wallet owners after the ledger data breach, calling them that they will visit them one day, although reported to be a call from another country and another languages were spoken. If your name, home address and ID card can be known in data breach, then are you safe? It is not common yet that criminals are not visiting crypto owners linked to data breach, but this could be possible in the future.
Another scenario of the information provided, data was breached by hackers, the hackers sent malware or phishing email to victims, the victims clicked on malware link or provided his seed phrase in a site provided in the email link while click on, or a link on the email that resembles the exchange they are using, just to scam the victims, many people have been scammed this way.
Kyc is extremely dangerous.
Another scenario, if exchange workers are linked to hack, then how wouldn't data breach be possible by them. Some sim swap attack is just because of insider unknown to people, also many bank account hack is as a result of bank workers. Criminals do not have it written on their forehead, nobody can be trusted, even government workers can not be trusted while yet the government are still third party, the exchange also have the kyc.
Kyc deprived people of privacy and makes people not safe.
I think the change addresses are usually the culprit in giving up someone's identity simply because they overlook it, then they accidentally link addresses together.
I'd agree with you regarding change addresses.
Also that almost all wallets do not have coin control and address freeze, it is the wallet that will do all itself and link many addresses utxo together while making transaction which is obvious on the blockchain, this makes almost all bitcoin wallet not recommendable as they do not have this coin control and address freeze feature and yet automatically and poorly selecting the coins while making transaction.
And if you ever decide to use coinjoin/mixer, you need to realize that the coin can't be deposited to to centralized exchange/custodial wallet without major problem such as locked account and demand to explain the coin.
I'd totally accept this, I do not know much about reputed mixers on this forum but likely the coins might not be seized (but just a guess), but CoinJoin could lead to coin seizure, I have read a post similar about this on this forum in the past about a reputed mixer on this forum:
I've never been banned while using ChipMixer on Binance, not saying that it is immune just that CoinJoins are a lot more obvious.
Although, be it mixer or CoinJoin, there is nothing bad to split the coins sending it to different addresses at different time period and making it up to or more than 5 hops for each. You are definitely right.