The trademark infringement is when their ad includes someone else's trademark.

Look at the screenshot in this post. All four of the ads at the top of the search results include the trademarked name "Midjourney" in the title of the ad.

This is more like putting up a giant sign outside of your Honda dealership saying "Best deals on new VWs!" but when you pull in they don't sell VWs, they sell their own competing products.

Some players circumvent this by creating "blog posts" where they compare/about multiple tools. Like it is a fair use but in reality is an ad in disguise.

Oh right. thats quite common! Pretty sneaky if you ask me

No, it's like searching for the location of a VW dealership on your phone and Google Maps taking you to an Honda one instead.

No, it’s more like a billboard saying, “looking for a Honda? ᶠᵒʳᵈˢ ᵃʳᵉ ᵇᵉᵗᵗᵉʳ ᵃⁿᵈ ʸᵒᵘ ᶜᵃⁿ ᵍᵉᵗ ᵗʰᵉᵐ here!

No, this is more like Honda putting a portal in front of the main door of the VW dealership that transports people into their showroom instead.