They've reduced size in every dimension, here's the 14 inch size from the specs for example:
Oled:
Height: 1.50 cm (0.59 inch)
Width: 31.08 cm (12.24 inches)
Depth: 21.63 cm (8.52 inches)
Weight (M5 Pro): 1.38 kg (3.0 pounds)
Weight (M5 Max): 1.40 kg (3.1 pounds)
Height: 1.55 cm (0.61 inch)
Width: 31.26 cm (12.31 inches)
Depth: 22.12 cm (8.71 inches)
Weight (M6): 1.55 kg (3.4 pounds)
Weight (M5 Pro): 1.60 kg (3.5 pounds)
Weight (M5 Max): 1.62 kg (3.6 pounds)
How do they compare to the 13/15/16” MBPs from 2016-2020 era (Intel CPUs and 4 USB-C ports)?
The 2020 Touch Bar 13" was 1.56cm x 30.4 cm x 21.2cm and 1.4kg, so this is the same weight, and thinner while having a slightly bigger footprint.