Chain analysis companies use many heuristics to link addresses into wallets.
The most popular being:
- common input heuristic where all addresses are grouped by the premise of being inputs to the same transaction
- change analysis heuristic which looks at the transaction outputs trying to group them by recipient and change address
- other methods, like grouping through SPV vulnerabilities, time analysis, pattern analysis
But the easier way of getting the identity of the address is (for the law enforcement) to subpoena the exchange, which will link your identity to any address you used to interact with this exchange. You can’t just “convert” bitcoin to Monero without using service like an exchange, or if you are really lucky you may try doing it P2P but this poses another set of risks.
But if you are looking into privacy features, I’d point you to implementations of coinjoin (Samourai, Wasabi, Joinmarket) which may help with breaking said heuristics.
Sources: https://en.bitcoin.it/wiki/Privacy
