Like the Witcher 3, which was absolutely stunning when it first released. Similarly (although originally a console exclusive) Red Dead Redemption 2 looks incredible on PC. We also have releases like Hellblade: Senuas Sacrifice which pushed the limit of what was possible to achieve with limited resources (regarding the development, not the hardware).
Honorable mentions should probably also include Star Citizen, which although still unreleased is definitely an incredibly technically ambitious project. As is Cyberpunk 2077. The launch might have been a total disaster, but afaik it's the first big game to ship a full ray-tracing renderer.
Maybe we have a different understanding of what a 'technically ambitious' game is. But I see technical improvements left and right. Unreal Engine 5 comes with some features that are just mind-blowing and make a whole new level of graphical fidelity available even to small indie developers. Just take a look at the recently released footage of "Unrecord", where lots of people thought it was real life footage.