Messages app shows some messages only as watch notifications and the message is nowhere else

I have an Apple Watch 10 no cellular connection. Most messages work with a notification on the watch and then I can read in Messages on my phone or Mac. However there are some messages that only appear as notifications on the watch and do not appear at all on the iPhone or any other device. How do I read these messages - and keep them as the notification just disappears on the watch? I think all these hidden and self deleting messages are SPAM.