First, ranting without substance brings a lot of noise to the conversation.
1. Try contacting Apple Support to walk through all options for notifications/alerts settings as many more options have become available with iOS 11. (800) APL-CARE or 800-275-2273 if you can't be bothered to spell it out.
(Pro Tip: if you are open to suggestions and willing to listen without interruptions, sometimes a solution arises.)
2. Saying it DISABLES ALL TEXT ALERTS on your iPhone permanently is false and you know that but if you would like to help the situation you are always able to send Feedback - iPhone - Apple
3. There absolutely is a (hide alerts) feature when pressing the ℹ on the side of a phone number or text thread as you can choose to hide alerts by individual or by group.
4. I also have the same issue and Bluetooth seems to be the factor at hand, because when it is turned off the phone allows me to receive text message alerts on lock screen with no problem.
5. For some people, they mentioned that deleting the conversation thread allowed them to receive notifications with no issue again.
6. For some people, particularly those who it happened with only one person, check that hide alerts was not enabled. To check this, two ways:
Slide from right to left and you will see (iOS 11) a blue box to [hide alerts] or red box to [delete]
-or-
see #3 above.
This frustrates me as well since I also own an Apple Watch and just want things to work. Remember everyone here wants to help solve the issue or offer suggestions, to which some might fit and some might not... That is what a forum is designed to help with for everyone, not a one size fits all. I do not think going to iOS 10 will resolve this as other people have mentioned this happening on iOS 10 as well.
Good luck because we are both in the same boat and hope a software update comes soon to resolve this.