https://medium.com/swlh/actors-using-scala-akka-part-2-askpattern-and-spawnprotocol-3942e45a5fcc

for {
    bankAccount <- bankAccountFuture
    balance1    <- bankAccount ? GetBalance
    _           = println(balance1)
    _           = bankAccount ! Deposit(200)
    _           = bankAccount ! Withdraw(50)
    balance2    <- bankAccount ? GetBalance
    _           = println(balance2)
  } yield ()

If this is intended to model transactions in a sequential stepwise fashion (e.g., deposit 200 then withdraw 50), this example is perhaps misleading.

I believe the order of sending (fire-and-forget/tell) messages in that map call are not necessarily the order that the recieving Actor would be processing the messages.

https://doc.akka.io/docs/akka/current/typed/interaction-patterns.html#fire-and-forget

To make the processing ordered, it would be necessary to use an ask and modify the message protocol to have return "response" message or status.

Something along the lines of this:

 val myFut = for {
   bankAccount <- bankAccountFuture
   balance1    <- bankAccount ? GetBalance
   msg1 <- bankAccount ? Deposit(200)
   msg2 <- bankAccount ? Withdraw(50)
   finalBalance    <- bankAccount ? GetBalance
  } yield finalBalance

Also, the actorSystem.terminate() call in your example can exit before all the futures have been processed. I suspect this needs an Await.result(myFut, Duration.Inf) call before the terminate() call of the actor system.