Need to be a bit careful with Youtube "facts" (and also subsim facts!). a couple of clips were used about eight times in that one video, and depth charges were shown when discussing hedgehog... Usually in the dark skies/seas series the script is much better than the video.
In real life the allies produced an ASDIC/hedgehog training film so incredibly boring it was used for many years by dentists during root canal treatment.
https://www.dailymotion.com/video/x7qjuo7
The problem with minimum range was more one of the fixed vertical angle at which the sound beam was projected (until late in the war). In fact the range at which contact was lost was a useful indicator of depth.
Equipment improved a lot later on but the allies never got good at establishing depth. A wide spread of depth charge settings would therefore be used. If you consider the small lethal radius of a few metres and the range of possible depths it is easy to see why the kill probability was very low, without even considering evasive manoeuvres. Conversely SH3 depth charge settings are so accurate that changing depth by 20m becomes a very reliable evasion technique.
On the other other hand game warships attack the last known position even if they have no contacts and the chances of a hit are about zero. Maybe it simulates attacking false returns from previous attacks? They give up after 20-40 minutes loss of contact instead of the late war recommended 24 hours, so stay quiet unless you are really sure they have you on ASDIC.
There's also the question of maximum settings for depth charges. I'm not very clear on this. Some sources say 300ft, increasing to 550ft very early in the war. Hard to square with the allies' operation of type VII submarine U570/HMS Graph. Other sources suggest 750ft. Sinking a deep submarine (200m/660ft or more) seemed really difficult to the end of the war and waiting for it to run out of air was often necessary.
Modders have done what they can, but the AI is hard coded in the original game.