GRX Cranks have a slightly wider chainline, as do a number of SRAM cranks which normally specify "Wide" somewhere in the naming scheme. Otherwise a number of direct mount 1x cranks can be fitted with chainrings of various offset if the crank arms themselves have adequate frame clearance.

Would be great to see some pictures with tires mounted up to see how the shapes look.

Yeah, I guess the metal bits do look extremely similar. The shaping of the carbon doesn't though. The Passquest seems to have much flatter faces with more rounded edges.

Strange. I'm no engineer but I wonder, given that steel is steel, why rotors would perform drastically differently. Maybe hardness / durability, heat dissipation, resistance to warping and what not, but I would have thought a steel rotor is a steel rotor, outside of "extreme" use (super long descent, heavy rider...).
I don't have enough experience with disc brakes myself to have formed a view from experience.
Given the prince difference between my rotors and what Shimano charges though, there would have to be quite literally a magical difference in performance for me to try Shimano ones.

I'm nearly an engineer and steel is definitely not just steel. The same steel alloy can have a factor of 4-5x difference in yield strength depending on how it is processed. A very famous example of variation in material properties is the ductile-brittle transition temperature. This transition temperature changes with the specific alloy of steel used. I'm not sure what properties make a good brake rotor but if you forced me to take a stab in the dark, I'd guess hardness is quite important. Again, this can have a very large spread across different steel alloys and even a pretty large spread within how those individual alloys are processed.

I really like the Onirii silicone bar tape. It's a little heavy but nice feel which you can customize pretty easily by how tightly you wrap it. Light tension for a bit thicker and softer. High tension for thinner and firmer.

If you want to reduce the weight of that part of your bike you are going to need to change the crank arms and not the chainrings.

I assume it is the latest video from Trace Velo on YouTube.