Quad SPI PCB layout

For FR4, using effective epsilon of 3.25 we get the wavelength of a 80 MHz signal in the PCB at 80 by calculating

wavelength = (c/f) * (1/sqrt(epsilon)) = (300000000 m/s / 80000000 1/s) * (1/sqrt(3.25) = 2.06 meters.

Using 1/16 of wavelength as the "safe limit" below which we don't need to worry about reflections and relative signal timing, it's

safe_length = (1/16)* wavelength = 2.06 / 16 = 12.8 centimeters = 5 inches.

Your signal traces are well below that limit. Your routing is good enough.

https://www.jlab.org/accel/eecad/pdf/050rfdesign.pdf

From a topology standpoint you may want to consider rotating the SPI Flash chip 90 degrees left (counter clockwise) as below. This will tend to even out the natural routing lengths and allow some possibility to length match up to the MCU.