Is there any mac/iOS app or feature I can use to alert me every five minutes?

I need an app or a feature on Mac, iPhone, or iPad that will send me a push notification or some kind of alert every five minutes.

I would rather not set up a million calendar alerts or alarms, as I will have to be using this a lot.

It will need to run in the background, especially if it's an ios app.

I would rather not use an iOS app that makes noise but doesn't send a push notification.

An iOS app is preferred, but anything works.

System alternatives will be accepted as well.

And no, I cannot simply ask Siri to do it, as I have tried in the past, and she says she can't do alerts that frequent.

Thank you for the help!