As said above, in IRAI i have reduced SONAR_DIFFICULTY_MAX = 0.85;
Result seems a lot better...meaning destroyers are still very dangerous, but now i have a little chance to escape IF manoeuvring correctly, and if i give them my thinner profile as often as possible
Not 100% safe though!...but better accuracy IMO.
(BTW, was testing this with FX Update test mission, and the 2 destroyers are damaging each other when launching depth charges!)