OK. I would qualify all that as pure American drivel (and from the quality of the trailer, I am staying miles away from that movie - puko-rama, if you know what I mean).
There were twelve escort groups (at a time) in the Atlantic to fight the Battle of the Atlantic. they were referred to by the identity of the country commanding the group. They were, respectively, B1 to B8, British groups; C1 to C5, Canadian groups; and, A3, American group (why it bore number 3, I have no idea, but there never were groups A1 or A2).
However, the American group was never full of American warships, so it had RCN and RN ships making up about 30% of its composition at all time, and no British or Canadian group ever had more than 10% of American units within them. Moreover, the Americans did NOT send destroyers to the escort groups. The American contribution to escorts was made up, for the largest part, of US Coast Guard cutters, which were not much better than corvettes even if somewhat larger, and of destroyer escorts, which were in reality British River class frigates built under license in the US.
In 1942, American warships fighting U-boats would not have known their port from their starboard yet, so fresh to the fight were they. It changed about a year later, but in 1942, they were worse than the Canadians.
By early 1944, the American group (A3) had been disbanded and replaced by the Canadian C5 group (The Barber pole squadron), while the remaining British groups (B2 to B8) were made up of about 65% of Canadian warships, while the Canadian groups were basically filed with about 85% Canadian warships. The Escort work had become Canadian, while the British and the few American warships concentrated on providing the Support groups (four of them), which were not assigned to nay convoys but roamed the Atlantic and either supported escort groups under sustained attacks or freely attacked and prosecuted to the maximum extent any concentration of U-boat they found.
The Atlantic U-boat war on the water was always a purely British/Canadian undertaking. The American greatest contribution was in providing air cover and escort carriers, not surface escort ships.
And BTW, the USN never had any Flower class corvettes, but the British and the Canadians did use a white/powder blue camo scheme on the North Atlantic escort ships, but not the Americans to my knowledge.