WHY is 5G connectivity so (Trash) unreliable on the T-Mobile network including their MVNO’s?!

The other day, I was waiting at the auto mechanic and overheard a conversation where the customer stated they did not receive notification their vehicle was ready the previous day(somewhat upset). The advisor stated they called them twice and left two voicemails - both parties proceeded to show each other's phones to indicate what they stated was true. I know one had an iPhone and I couldn't tell the other, it had a case so I wasn't sure.

The advisor says something, something always has an issue with our phones blasé blah, T-Mobile, something something. 

I thought about intervening, and ultimately deciding not to. Millions of people use their cellphones everyday. I don't even know where to begin, the extent of this issue is crazy and the fact most people are not even aware is how they are getting away with it. What if that was a call/voicemail/sms from the hospital about a loved one. The severity of this matter seems to go over people's heads and anytime someone brings this up - the way some people dismiss it is ridiculous. Never had these issues on older cellular tech - 5G is just not reliable for communication - these missed communications can be ruining people's lives and they dont even know it is happening smh....

On my business device with dual SIM (primary SIM 5G on data preferred, second SIM 5G off voice sms preferred) - I got an OTP from bank, it did not come, I wait, nothing, I go into settings - disable 5G, the text came through instantly. 

Unacceptable.