If I transfer BTC to a friend/family, they now know my wallet address, correct? Does this mean they can see all the transactions I have done from that wallet? It seems like wallet information is public except for identity, but that would be forfeited once I make a transfer, right?
If you send Bitcoin directly form your wallet then receiver will be able to know exact amount of coins you have on your address or addresses.
Good address management can reduce this, and you can also use coinjoin or mixers like ChipMixer to remove connection with your original address.
Sending coins form your exchange account is also an option, but much more risky because they can lock your account and freeze your coins at any time and for any reason.
mixers are the best way to keep them from seeing the contents of your wallet. Actually there are several ways other than that, but the method is quite inconvenient, like having 2 wallets. the first wallet is for savings purposes, while the second wallet is for transactions. well, even though he could send assets from wallet 1 to 2, and still be tracked, he just had to prepare an excuse for that. This is the same as an exchange, only the difference lies in the fee. the fee on the exchange may be higher, but it is safer. while sending from wallet to wallet is still at risk of being caught, it's just that the fee is less. well, if you don't want to bother like that, mixers are the best way.