Bike recommendation

Hiii I’m thinking in buying a bike to commute to work, going to the park, maybe the gym. Trips around 2 to 3 miles. Mostly paved, just the trail at the park is gravel. Not completely flat though. There are some up and downs like mini hills.

I’m overwhelmed with so many options at department stores. And big brands like Trek or Specialized are sooo expensive.

I have a back problem so ideally could use a back suspension besotes the fork one at the front. Also I’m 5 foot 7 aaaand 250 pounds so it has to be tough enough for a heavy guy like me (actually I want to start riding a bike as a weight loss exercise).

Any recommendations of some entry level bike not so expensive but reliable for daily commuting? As a reference, I don’t think I can pay more than 500 usd right now.

If you got this far, thank you for reading!