Both of my twin girls have tantrumed but it has likely been for different reasons. One was hyper responsive and the other hypo. They are now 8 and doing very well.
OT, listening therapy and recognizing when they were getting out of sync has helped enormously. Also, for one, who is not a big eater, paying attention to her food intake has helped. In our case, some yoga, resistance, a quick jump on the trampoline or a run around the block when I see that they are getting unregulated typically does the trick.
Also - likely not an issue for your son - but one of my daughter's had seriously compromised vision, which led her to be off balance, and have double vision frequently.
While I knew that she had strabismus, I did not get good information from a serious of pediatric ophthalmologists and didn't realize how much her vision was impacting her behavior until we addressed this area.
So I have many strange behaviors but I've usually assumed it was my social anxiety until I came across something on the internet about Sensory Defensive
I'm a teen who was diagnosed with level 1 autism at age 13. Since I was very young I had sensory issues, they were very noticeable when I was in preschool,