Hamburgers, how to make juicy ones

I've been making burgers since i went to Ireland and we set up BBQ in Kilkenny. We had mixed mince with egg and breadcrumbs and onion to make the patties.
Overall I've started to become dissapointed with the patties. They are not too flavoursome, so I started looking on Mr YT to see what other say.
I did watch a few videos on avariety of burgers made around the US, and there were a lot of different variations. But what I wantedwas the basic burger & patty.
The video below is the one I've folowed, and although the people look a bit stiff and Dormant (they do not look at each other a lot and rather look as if they are in a line for inspection, what they say works well for me. 

Basically, up until recently, I've been doing it all wrong.

1.  Basic mince only, no extras such as breadcrumbs or onion.
2.  High fat content, alla cheap mince, fat content about 20%
3. Shape patty and leave, not a lot of fiddling to shape it. 
4.  Indent in centre with thumb on one side (the first side down to grill) so that it stays in shape.
5. Leave in fridge for 10-15 minutes to cool down after working it with your hands (which has warmed it up). 
6. No oil in the frying pan, its got enough fat in the burgers, and cranked on high, this can be reduced to medium high after a time.
7. Season it and put it on grill and leave it for 2-3 minutes, do not tough again until you turn once to cook 2nd side (after seasoning)
8.  See sides turning brown and this is indication that its about cooked on one side.
9.  Let it rest for a couple of minutes to re-absorb juice, stops buns being wet and sodden.
10. Toast buns lightly, so they don't burn.
11.  Chuck it in the buns with your condiments and wolf it down. Mayonaise and lettuce under, onion, tomato, mustard/ and/or tom sauce over

I have done this the last time I got some mince and the man is right, it is nice and Juicy. I really enjoyed it.
I did find my patties were a bit small in diameter but thick, I didn't want to over play with the patty so I left it in that configuration. I think i've just done it again, so I'll just have to practice lots to get the diameter and thickness correct.
I'm thinking 50g of mince should make 4 patties , so $7 for 500g, so 3.50$ for meat for meal, plus buns and condiments and lettuce etc.

A couple of hamburgers, some air fried chips  and coleslaw and I really struggle to finish the meal, I'm absolutely chock full. An extremely juicy burge.
I always think these are a bit of a laugh but it does show contrasts on cooking styles:

Hamburger buns

  These i haven't made. I havent bought them for a while, but have recently got into buying a bag of 6 or 8 and freezing all but 2 that I want to use for a meal.
This is food wishes take on making thebuns, it looks good so I may give it a try (although I'd add the salt after I added the flour)

Here is his ingredients list (https://foodwishes.blogspot.com/2013/07/homemade-hamburger-buns-oh-my-god-becky.html):

Ingredients for 8 large hamburger buns:

1 package (2 1/2 tsp) dry active yeast (I used Fleischmann's “RapidRise” Yeast)

1 cup very warm water

1 large egg

3 tablespoons butter

3 tablespoons sugar

1 1/4 teaspoons salt

1 pound all-purpose flour (about 3 1/2 cups)
Note: add a 1/2 cup of the flour to the yeast and water, and then the remainder before kneading
 

for the tops:

1 egg beaten with 1 tbsp milk

sesame seeds

*bake at 375 degrees F. for 15-17 minutes

Chips

I use frozen chiops and air fry them, the thicker seem to be better, the shoelace ones are a bit thin for me. Or else bandito wedges with a bit of zing, although I do like Sour Cream with them. 

Coleslaw. 

Cabbage, carrots and onion and some mayonnaise. That seems to do the trick.