I'm pretty sure this started right after I switched from a Postplaid family plan to a Prepaid individual plan in August. Since then, often I will send a text message, and either it will arrive several hours to a day later, or it will not be delivered at all. I text one person steadily almost every day, and it seems to occur once every day or two. Details about my device: I had a Galaxy S8 before and since November a Pixel 3a. I originally was using the Message+ app, but switched to a 3rd party messaging app to see if that would solve the issue. It did not.
Is there a way to fix this? Or could Prepaid plans have lower priority in cell signal usage, resulting in lost texts or cell connection?