except it is somehow linked manually.
How do blockchain experts address this issue
There's no issue here.
I think that's what OP was trying to say, linking the KYC manually can't be erased, it stays with the address forver.
This creates potential vulnerabilities as future data discoveries or new technologies may reveal additional information.
How do blockchain experts address this issue?
OP, since address that you use on a Centralised exchange that's passed KYC is the only thing affected, the day you decide to change to fully privacy all you need to do is abandoned the old address and create a new wallet address.
Never use the address anymore and that is the end, continues using of the address is what carries your data information everywhere else, abandoning the address put an end to it.
All you need to do is never use the new wallet address on any exchanges ever, and stay away from passing any online verification, learn more about privacy and start using P2P platform instead.