I mentioned that I am not only the mother of an autistic child, but I have worked as a TA supporting a child with ASD, that is with different children. I am referring to my own experience.
Children with ASD are not challenging for all of the time, as a rule. It was , indeed, quite relaxing down time' for me to sit while the children listened to the assembly, because my charges were not difficult, at all times. I would keep my eyes trained on them, but often no response was needed. And this is the nature of the job: there are times of being very active and times when it is more about being attentive, but allowing the child to explore, in their learning.
This is getting silly, because many people apply to work as TAs, in many areas, and the job is not unrelenting misery. Nor would the presentations of ASD have changed across the population, since I worked in schools as an LSA. It can't be the case that children who display challenging behaviour are in crisis, continuously, now in 2023, when they were not when I last worked in school.
. Children with ASD do sit quietly, for some of the time. As a TA, you will be skilled and experienced, and there will be periods of down time, relatively speaking. Relative that is, to other jobs, such as working in a small supermarket or a cafe, where you would be constantly serving or arranging stock, and constantly on the go. . That is the nature of the caring role, that there are times of intense activity and times when your input is not required, on a minute to minute basis.
It is possible, that more children with SEN are being taught in mainstream than previously. But, I think management and knowing how to support learners is important, wherever children are taught.. In my son's special school, there were challenges, but the staff, by and large enjoyed working there, and if they didn't, it had more to do with the management style, than the behaviour of the children. Staff had been working in that setting for more than 20 years. They felt that they belonged to a team and that they had support from colleagues. They were suited to the work. Some of them had children or nephews with ASD, and so they knew what to expect and had understanding.
Of course staff rotate. That would be good practice.
In your place if work, do you really say: 'This child is violent'? Do you not express it: 'This child may display behaviour which challenges?' Much has changed, perhaps.