Typical Hollywood WWII movie If you call the movie Greyhound in reference to an actual and current naval battle tactic, than you should pay more attention to the reality of submarine / subsurface warfare.
In that context even the movie Battleship did that much better.
1. The German agenda during these days in the Atlantic was to sink as many merchant vessels as possible and definitely not to get head on head with allied destroyers.
2. Submarines are vessels of stealth and silence and they accomplish their missions with precision and patience.
3. The goal of the allied forces was to get their convoy safely to the British coast and to defend the cargo ships. In order to achieve that the destroyers had to stay in their sectors to shield the convoy as good as possible. They didn't hunt the submarines they chased them of. They didn't actively hunt them because that would leave the rest of the convoy without protection.
There is a reason why convoy-duty is to this day considered boring.
The movie is generally an action movie like pearl harbour and so forth. There's not much depth to it so you can watch it on an evening if you need something entertaining.