So, you don't rate Southgate on one hand and, on the other, think England fans wanting an upgrade on him is impossible because, according to you, this "mythological" manager "doesn't exist"? A manager who would be an improvement on Southgate doesn't exist...
Every single one of our exists were due to tactical decisions, but, sure, the manager is the last reason. The "last and least". He's just being scapegoated like every England manager ever who all showed how great they were after leaving the England job, which I'm sure Southgate will do, too.