There are too many factors one on top of another and without letting a bit of time pass, it is very difficult to say what is driving the increase in diagnosis.
Often this is due even to a weird way of reporting that is not adjusted to changes in way of diagnosis or previous underreporting.

There have been changes in how the diagnosis is given, including that other diagnoses such as Asperger's are now included in ASD and also people who are relatively well adjusted but still neurodivergent can get a diagnosis now, which makes sense, as one needs accommodations and understanding.

This doesn't mean that we shouldn't use the precautionary principle and, based on previous experience that shows infections are not a good thing, especially in early childhood, we shouldn't reduce as much as possible infections in children via better prevention, such as ventilation and filtration.

We will see how SARSCOV2 influenced children's neurodevelopment only after a decade or so, as it takes time for trends to become visible and to be validated as a trend, rather than as a temporary situation.
Regarding youth's health, probably it will take a decade or two before we have a full picture

Given that the biggest increases seem to be in teenagers, and that it is known changes associated with autism happen before birth, at least for youth these increases in diagnosis are most likely due to better knowledge and awareness. Puberty brings new challenges & can reveal a need for diagnosis.

Hubris, plenty of hubris.
And also a strong ableism and greed.