How to escape from Siri text message dictation?

Background info: I have an iPhone 8, with software version 13.2.3. It looks like a new patch is ready for the phone and will be installed tonight

I use Siri to read and send text messages while driving and have for some time now without issues. Lately, when composing text messages, Siri waits apparently forever after I have finished speaking. Siri remains in listening mode and never reads my message back nor asks if I am ready to send it. I have let it go for about 5 minutes as an experiment and it seems that Siri is intent on remaining in listening mode forever. This happens when I say "Hey Siri, send a text message to XXXXX" but do not immediately include the message in the request. When Siri then asks what I would like to send as the message, it will hang like this after I am finished speaking regardless of what I dictate as the message. Also, if I have Siri read a message I received and then say I want to reply to it, it also hangs. The *only* way it does not hang is if I immediately include the message to be sent as a part of the request. There appears to be no keyword (at least that I can find) to let Siri know I am finished speaking, but it sure seems like there ought to be some word that can be used to "escape" from the input via voice process and then finish the process of sending the text, but it seems there is not. I wondered if road noise had anything to do with this, but the vehicle is not real loud inside and even when driving slowly with little to no road noise it still occurs. I would like to think Siri would be able to distinguish between speaking and road noise with no speaking in any event and would anticipate a certain level of road noise since the intent of this feature is largely to allow hands-free phone use while driving.

Is there any way to let Siri know I am finished dictating my message and to stop waiting without touching the phone which is unsafe (and even by touching there seems to be no way to end the input short of canceling the whole process and losing what was dictated)? Does anyone else have this issue, or is it just me? I am hoping there is some way to work around this since it is very inconvenient not to be able to directly reply or to have to immediately dictate the whole message as a part of the send text message command, and this issue effectively prevents me from using the reply feature when prompted after having Siri read a message.

Any suggestions you can provide me would be greatly appreciated.