The only coupling that is backlash free and can handle misalignment in two planes is the Oldham coupling.
There are other types accommodating misalignment in two planes John.
This is a photo of an assortment from my coupling drawer.
The four on the left are all zero backlash and allow slight misalignment in two planes and angular misalignment. They tend to be very expensive but, in my experience, are used in the applications requiring greatest accuracy and reliability.There are versions of this type of coupling with only one flexible driving plate - these are cheaper but only compensate for angular misalignment.
Your favoured Oldham coupling (3rd from L on top row) will accommodate much more misalignment but it can come at a cost of lifetime. The more off-axis the motor and leadscrew the more sliding between the three parts and therefore wear and eventually backlash. They are 'relatively' cheap and ideal for home CNC projects.
The aluminium coupling at bottom right will take small amounts of misalignment in all planes but if they are not well aligned they will fatigue. They are also very springy so, if the table you are trying to move has any friction, a step or two at the stepping motor might well not move the table at all and just wind the 'spring' up.
I agree that the Lovejoy type of coupling will only compensate for angular misalignment.