The Simulacrum spell states:
You shape an illusory duplicate of one beast or humanoid that is within range for the entire casting time of the spell. The duplicate is a creature, partially real and formed from ice or snow, and it can take actions and otherwise be affected as a normal creature. It appears to be the same as the original, but it has half the creature's hit point maximum and is formed without any equipment. Otherwise, the illusion uses all the statistics of the creature it duplicates, except that it is a construct.
True Polymorph states:
Choose one creature or nonmagical object that you can see within range. You transform the creature into a different creature [...]
Creature into Creature. If you turn a creature into another kind of creature, the new form can be any kind you choose whose challenge rating is equal to or less than the target's (or its level, if the target doesn't have a challenge rating). The target's game statistics, including mental ability scores, are replaced by the statistics of the new form. It retains its alignment and personality.
If you make a Simulacrum of a True Polymorphed creature, do you...
Get a copy of the original creature which happens to be true polymorphed, so dispelling the true polymorph, or reducing the true polymorphed form to 0 hit points, will yield you a simulacrum of the original?
Get a copy of the true polymorphed version of the creature?
(For simplicity, assume that both the initial and true polymorphed versions of the creature are humanoid or beast.)