I think that all uniqueness techniques require the puzzle to be unique in the first place, which yours is not. Even if you stated the uniqueness in the puzzle description, this would be a lie, since the puzzle does definitely have 3 solutions.
What could be stated is something along the lines of: At some point on the solving path you will have to make a choice for a cell that leads to a unique solution after that choice is made and all other choices don't lead to a unique solution after the choice is made.
But that does not make the puzzle unique and it is questionable if said choice for the cell is in any way better than the others. It is just the first uniqueness related joice to be made in a particular solution path that avoids making further uniqueness related choices.
In the interest of keeping mental sanity it s probably advisable to think in this way:
Every unique sudoku can be solved by other means (which in the case of BUG are typically XY-chains, but in the extreme case might just be brute force) and uniqueness techniques may provide shortcuts to that one solution.
What could be stated is something along the lines of: At some point on the solving path you will have to make a choice for a cell that leads to a unique solution after that choice is made and all other choices don't lead to a unique solution after the choice is made.
But that does not make the puzzle unique and it is questionable if said choice for the cell is in any way better than the others. It is just the first uniqueness related joice to be made in a particular solution path that avoids making further uniqueness related choices.
In the interest of keeping mental sanity it s probably advisable to think in this way:
Every unique sudoku can be solved by other means (which in the case of BUG are typically XY-chains, but in the extreme case might just be brute force) and uniqueness techniques may provide shortcuts to that one solution.