Where the damage lands
Queries with a single factual answer are the worst affected. If someone asks what a term means and the answer fits in a box, there is no reason to click. Publishers who built traffic on that content have taken the heaviest losses.
Queries where the person needs to see, compare or buy something behave very differently. An Overview cannot show them the product, the price or the availability.
What to do about it
Rebalance towards content that survives. Comparisons, pricing, calculators, anything with a real product behind it. That content also happens to convert better, so the shift is not a loss.
For the informational content you keep, accept the trade. Being the cited source in an Overview builds brand recognition even with no click, and it feeds the assistants at the same time.
Measure it properly
Stop reading total sessions as the health metric. Track impressions, clicks and CTR split by query intent, plus branded search volume as a proxy for whether the visibility is landing. Branded search rising while informational clicks fall is a good outcome and should be read as one.