I have a Huawei P20 Lite but can't find a setting for a reminder if there is an unread text message.

[Android Central Question]

If you don't hear the new text message sound or are unable to look at the phone when a new message arrived there is no audible reminder.

 

[B. Diddy]

Welcome to Android Central! The notification reminder feature isn't native to Android -- I think it's mostly on Samsung phones. You could try Missed Notifications Reminder.