Because anti-competitive behavior in this context cannot be performed by someone without a monopoly.

Apple cannot be anti-competitive in the search space unless you show they have a monopoly on browser apps (which you could, but would probably fail based on how the Apple lawsuit is going).

I'm not referring to the specific context of this lawsuit, but the broader context in general.

Google is in multiple anti-competitive lawsuits, while Apple has the most walled garden of all gardens, protects it with a giant club and manages to get away without a scratch. For example Google got sued for anti-competitive practices in Android regarding third party stores, Apple gets no such lawsuit because they simply made it impossible.

Of course it's the laws to blame since they incentivize aggressively closed ecosystems from the get go, but it's odd that there isn't even a conversation about it regarding Apple.