Do papers need a "non-conflict of interest" disclosure nowadays to not be considered just ads?

When they are studying a consumer product it is pretty customary to declare a non-conflict of interest. So yes. Declare it at the end of your paper please.

Unless you have a conflict of interest, in which case declare e.g. “the lead author of this paper is an Associate Director and Senior Fellow at HAI which receives funding from Google the company which makes Gemini”.