Overview:
The key is working out which cell governs everything.
That cell is [elided] - what values can it take?
Nope, not that, nor that, nor the others - yes, it has to be that one value.
And everything drops into place pretty darm quickly after that.

Do you really need a hand-holding walkthrough?

Proof of uniqueness:
https://sigh.github.io/Interactive-Sudoku-Solver/?q=.Thermo%7ER4C4%7ER3C4%7ER2C4%7ER1C4.Thermo%7ER4C6%7ER3C6%7ER2C6%7ER1C6.Thermo%7ER5C8%7ER4C8%7ER3C8%7ER2C8%7ER1C8.Thermo%7ER5C2%7ER4C2%7ER3C2%7ER2C2%7ER1C2.Thermo%7ER8C3%7ER7C3%7ER6C3%7ER5C3.Thermo%7ER8C7%7ER7C7%7ER6C7%7ER5C7.Thermo%7ER6C5%7ER5C5%7ER4C5.Modular%7E3%7ER1C2%7ER2C2%7ER3C2%7ER4C2%7ER5C2.Modular%7E3%7ER1C4%7ER2C4%7ER3C4%7ER4C4.Modular%7E3%7ER1C6%7ER2C6%7ER3C6%7ER4C6.Modular%7E3%7ER1C8%7ER2C8%7ER3C8%7ER4C8%7ER5C8.Modular%7E3%7ER8C3%7ER7C3%7ER6C3%7ER5C3.Modular%7E3%7ER8C7%7ER7C7%7ER6C7%7ER5C7.Modular%7E3%7ER6C5%7ER5C5%7ER4C5.Arrow%7ER5C3%7ER5C2%7ER4C3%7ER4C4.Arrow%7ER5C7%7ER5C8%7ER4C7%7ER4C6.Arrow%7ER9C5%7ER8C6%7ER8C7.Arrow%7ER9C5%7ER8C4%7ER8C3.Arrow%7ER1C4%7ER1C5%7ER1C6.Arrow%7ER1C4%7ER1C3%7ER1C2.Arrow%7ER1C8%7ER1C7%7ER1C6

The elided cell identifier is r1c6.