How to sign a P2SH(P2WSH) transaction?

var alice = new SafeAccount(id: 2);
                var aliceAddress = safe.GetAddress(index: 1, hdPathType: HdPathType.Receive, account: alice);
                var alicePrivate = safe.FindPrivateKey(aliceAddress, account: alice); // safe.GetPrivateKey(index: 1, hdPathType: HdPathType.Receive, account: alice);

                var david = new SafeAccount(id: 3);
                var davidAddress = safe.GetAddress(index: 1, hdPathType: HdPathType.Receive, account: david);
                var davidPrivate = safe.FindPrivateKey(davidAddress, account: david); 
             
                Script redeemScript =
                    PayToMultiSigTemplate.Instance.GenerateScriptPubKey(
                        2,
                        alicePrivate.PrivateKey.PubKey, davidPrivate.PrivateKey.PubKey);

                var received = new Transaction();
                received.Outputs.Add(new TxOut(Money.Coins(0.0021m), redeemScript.WitHash.ScriptPubKey.Hash.ScriptPubKey));

                ScriptCoin bobAliceScriptCoin = received.Outputs.AsCoins().First().ToScriptCoin(redeemScript);

                var builder2 = new TransactionBuilder();
                var tx2 = builder2
                        .AddCoins(bobAliceScriptCoin)
                        .AddKeys(alicePrivate, davidPrivate)
                        .Send(addressToSend, Money.Coins(0.002m))
                        .SetChange(aliceAddress)
                        .SendFees(Money.Coins(0.0001m))
                        .BuildTransaction(true);
                Console.WriteLine(builder2.Verify(tx2));

I would like to sign a P2SH(P2WSH) transaction but failed. Anyone can help to review the below codes?