Losing Service Constantly

Hello, I have the iPhone 8 and it’s less than a year old, I believe I got it last June or so. I lose service about every 5 minutes - I am not even exaggerating at all - and I have to turn it off and on again. It is INCREDIBLY frustrating as my job is reliant on communicating with my clients, and my messages don’t send and transit apps don’t load so I end up being late. I went to verizon a few months ago and they replaced my sim card; that didn’t change anything. What else should I do to stop this from happening??

Thanks

Mackenna