Nice question, good way of framing things.
For me (presently), it's a tie between two razors, both give efficient and close shaves with little effort, and are very easy to dial in:
__ the little known Danish made 1930s vintage OC slant, called Raadvad "Mejeskær",
__ and, the better known Razorock stainless steel Lupo .72
I’d have no hesitation recommending any of these to someone who had never shaved with a DE. The Jagger was my first “proper” DE razor after a Wilkinson Sword Classic (black plastic) and I feel my technique came on leaps and bounds with the Jagger, to the point I felt ready to try a Merkur Futur around 6 months in.
I didn’t use a 42C or King C Gillette until 7-8 years after I first shaved with a DE but I find both to be similarly user friendly to the DE89.
Believe it or not, it's this big honking piece of steel, the Holy Black SR71.
This thing has not given me one bad shave, not even a meh shave. Every shave has been outstanding, leaving my face like glass without any irritation. It's so heavy it just glides effortlessly through the whiskers. I could shut my brain off while shaving with this gentle giant. While it looks mean and nasty, I don't think I could cut myself if I tried.
Among DE’s, my Gillette SuperAdjustable is the easiest to use. Easy BBS everytime.
Of all the razors I’ve used, I’d say the Schick G is the most user-friendly. Effortless BBS, no technique required. The Schick injectors are the best razors in the world.
This is a tough one...I am still fairly new and learning a ton so I can't narrow it down to just one but the "most user friendly" razors and blades to shave with are (in no particular order):
Karve Bison green aluminum
Henson +/++ "frankhenson" black & silver (I swapped handles with the + and ++ one black and one silver)
Blackland Blackbird Lite stainless
Rockwell 6S stainless red & black (I have one of each color)
Blades: Nacet, GSB, Gillette Platinum, Permasharp, and Personna
After all that, if I could only pick one at this point in my "shaving career", it would probably be the Blackbird Lite with a Nacet.