Watch at service, alternatives?

Hi

Sending my watch to service for a warranty issue and I cant run without a watch haha.

Was considering just buying one at a 60 day free return and return it once I get my old one back. But now im thinking I might get the HRM pro plus strap instead. Can I use just the strap and still track my runs and everything? And how do I do it? Google gives me so many different answers. I use the garmin app, but im also synced with Strava.

Thanks!