I think you also had a similar comment and linked the same article under the previous topic about JWST's first image?
The article is very informative, but my read of it is different: the three major "spikes" are in fact due to the hexagonal shape of the mirrors and how they're laid out. The struts also add three spikes, but: two of them coincide with the mirror spikes, while one of them (from the vertical strut) is visible on its own, and causes the smaller perfectly horizontal spike.
The image I'm basing this on is in your article with a caption starting from "The point spread function for the James Webb Space Telescope" [1]
Hubble shows four spikes because it has two struts.
https://bigthink.com/starts-with-a-bang/james-webb-spikes/
https://www.universetoday.com/155062/wondering-about-the-6-r...