Do not disturb is very disturbing

So this year I switched to iOS from Android and the experience has been good so far except for the DnD feature. DnD has been inconsistent, sometimes it blocks and silences everything and some other times it doesn’t work at all (feature is turned on).

Last week DnD on my iPhone allowed a spam call twice on my device around 6 am ( on my day off) waking me up. Yesterday I was taking a nap and before my nap and I did make sure DnD was on (also I have share across device /mirror my iPhone options enabled) and my Apple watch showed the purple DnD icon but device still started beeping 5 mins later (it allowed Telegram notifications) and of course my nap session was disturbed. Over Android when you activate DnD, it means complete silence no matter what but iOS DnD seems buggy.

BTW my “DnD notifications options” are all set to “none allowed”. Am I doing something wrong? Or the only way to completely silence an Apple device is turning it off?

thanks