Checked sensor files I noticed that even early radars have very long range which is unrealistic.
For example Type 271 ( first radar used for corvettes)
Could detect surfaced submarine at 4,8km
Source:
https://en.wikipedia.org/wiki/Type_271_radar
In your modpack it has max range of 10km!
And the radar amount of radars were in limited quantity
Wikipedia quote
The prototype,
271X, was fitted to
HMS Orchis in March 1941 and declared operational in May. Small numbers became available during the year, with about thirty sets in operation by October.