I detect not only the moving but abduction to another playing field of your goalposts.
Neither of those diagrams resemble yours in post #32, to which I've been working, and which you have insisted is immutable.
Your design still won't work, but before I put any more effort into it, confirm that this topology is final. Your lack of understanding of why it can't work does not not bode well.
In particluar , why does your resistor to be measured (R1) have to sit between two other resistors?
Why can't one end be earthed?
And why can't I put a simple current source into it and dispose of your 'load' resistors? ( which dissipate a lot of power to no obvious purpose..)
If you made it clear what you're actually trying to measure, and the essential electrical conditions under which it must operate ( and perhaps why) I might find a neat answer.
Having been given only partial information I and others may well have been on a timewasting wild goose chase.
Allan.