You hardly need any hints for this one.
Start in box 9, and work your way around the connections.
Everything just drops out almost instantly

Proof of uniqueness:
https://sigh.github.io/Interactive-Sudoku-Solver/?q=.Arrow%7ER3C3%7ER3C4%7ER2C5.Arrow%7ER3C7%7ER4C7%7ER5C8.Arrow%7ER5C8%7ER6C8%7ER7C9.Arrow%7ER3C7%7ER2C6%7ER2C5.Arrow%7ER8C7%7ER7C8%7ER7C9.Arrow%7ER7C5%7ER8C6%7ER8C7.Arrow%7ER7C5%7ER6C4%7ER6C3.Arrow%7ER5C2%7ER4C2%7ER3C3.Arrow%7ER7C1%7ER8C2%7ER9C2.Arrow%7ER3C2%7ER2C2%7ER1C1.DoubleArrow%7ER3C3%7ER2C4%7ER2C5.DoubleArrow%7ER3C7%7ER4C8%7ER5C8.DoubleArrow%7ER5C8%7ER6C9%7ER7C9.DoubleArrow%7ER2C5%7ER3C6%7ER3C7.DoubleArrow%7ER8C7%7ER8C8%7ER7C9.DoubleArrow%7ER7C5%7ER7C6%7ER8C7.DoubleArrow%7ER7C5%7ER7C4%7ER6C3.DoubleArrow%7ER5C2%7ER4C3%7ER3C3.DoubleArrow%7ER7C1%7ER8C1%7ER9C2.DoubleArrow%7ER3C2%7ER2C1%7ER1C1