Some colorimeters are accurate others are not. Both could be corrected with the help of a spectrophotometer: your spectrophotometer and your colorimeter measuring your display… or for some colorimeters a set of spectral samples of very common backlights.
Spyders are not as accurate as they should be. Even if they were a litle more accurate they would need some kind of correction. Here you have 2 sources of errors or uncertainties when you try to measure your widegamut laptop with a Spyder.
If you do not wish to buy a more accurate device your best chance is to use your Spyder5 with DisplayCAL and selecting RGBLED correction from Spyder bundle of corrections. I do not know if the name is exactly RGBLED, it could be “widegamut LED” or something similar (which is usually different from “WLED”)… but it is a spectral sample of an RGB-LED display.
Your laptop is very unlikely to be of that backlight but it is the closest.
Even applying that correction it is possible that readings are wrong because as explained earlier Spyders are not as accurate as they should be.
Test again with this setup and choose a fast calibration with a matrix profile. I mean to test if there are improvements in % coverage without wasting too much time on this task.