For anchor points they could easily weld additional steel plates/rings at numerous points on the hull for a many lines spread out.
Maybe place some cables under the front section attached to airbags. It would not lift it off the sand but may help with downward pressure on the pull back + the excavator work.
Also cant you vibrate/aerate sand to make it have a liquid effect? Might help pressure but no idea how that could be done at scale required... winches and cable seems easy to access fast.
-- the Ever Given has a mass of ~220,000 tons (2.2e8 kg)
-- let us very conservatively assume that it is a homogeneous block, 1/3rd of which is on sand, 2/3rds of which is on water
-- the Coulomb coefficient of friction for steel on sand is a very complex function of sand composition and size, but roughly it's about µ=0.5 and F=µR [1]
-- For the 2/3rds of the ship that are in the water assume that it moves frictionlessly in an inviscid liquid (not true at all else ships wouldn't have huge engines!)
-- You therefore need to apply a net tension of ≥0.3 x 0.5 x 2.2e8 ≈ 33 MN to a wire to have a remote chance in hell of accelerating the ship backwards
-- This is about twice the thrust of a Space Shuttle solid rocket booster at liftoff.
[1] https://www.jstage.jst.go.jp/article/sandf1972/26/4/26_4_139...
I'll start with my guess: A long time
US Military is probably the only entity that could pull this off in a timely manner. At great cost of course...
Russian Military has: https://en.wikipedia.org/wiki/Mil_Mi-26
That's the one they've used to rescue downed US helicopters :)
Looks like a 40ft shipping container weights around 8000lbs empty, couldn't find a stat on full. It seems such an operation would be outside the capacity of these helicopters. Sure they could comfortably lift empty containers, but probably not full ones.
And yeah, even completely empty with no fuel or ballast you will never see the bow out of the water like that. However it is more than capable of surviving being dragged along sand. It's just that they have nothing strong enough to drag it with.
Eventually someone will stake some anchors into the ground and use an industrial winch, but that's where hull design starts to suck - there's no good anchor points by which to pull it, so there'll need to be a large number of straps cradling the hull that are being pulled.