if two teammates on your team each have 5 deaths before 10 minutes that match is over

Pretty much, but they never surrender and waste my time. I really don't understand how stupid some people are, they keep playing as if it matters that much if they win that one game at 35-40 minutes, if they get lucky that enemy throws, they don't learn much from such game and if you want to get better it is all about improving. Currently it is quite an early game meta, meaning first 10 minutes are pretty much what will show who will win or lose if enemy team doesn't throw. So it really is the most important for you to play first 10 minutes of the game over and over until you know how to do everything perfectly, yes games don't end at 10 minutes but they snowball so hard that you can't catch up even with bounties unless enemy team throws.

They should create an in game tutorial on how not to die lv 1 and 2.

Then everyone who has 5 deaths at 10 mins is instabanned from playing Normals and Ranked until they successfully finish that tutorial 5 times.