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.