I think any breed of cattle can be calm is they are properly socialized and if you pay attention to disposition in your breeding program. We raise Texas Longhorns and from the old westerns, most people think they have a ratty disposition. Our bloodlines have been worked on for 50 years to have docile dispositions.
Back in the 80's we raised Salers for a few years. We purchased semen from a well known and respected imported bull. All the calves from that bull were absolutely crazy. You couldn't halter break them and they would run over you in a heart beat. After asking around a little to other breeders, everybody had the same experience with that bull. We learned that disposition can be genetic.
Every bull that we use here is assigned a "chute score." Here is an article at the University of Nebraska explaining how that works. 1=Docile, 2=Slightly Restless, 3=Restless, 4=Nervious, 5=Flighty or wild, and 6=Agressive.
If that bull's chute score is 4 or higher, he becomes a steer and has a new career as a "Feedlot Steer" or a "roper."
As a result of doing that for 50 years, we rarely have one that scores above a 3 unless we AI to an outside bloodline.
I believe that cattle with a higher IQ are more docile than cattle with low IQ's.
Here is an article that my father wrote back in 2020 about "Cattle Intelligence Testing."
https://www.texaslonghorn.com/pr/index.cfm?story=enews-213_Cattle_IQ_20200605&year=2020