Hi @Dorthy1 - yes, the rate at which you write guest reviews affects the guest favorite of 1%, 5%, 10% opportunity. It does not affect the general 'guest favorite' (currently).
We attended a zoom call when guest favorite was first introduced and the AIRBNB person shared this information. She indicated that it was like 80% at that time, but in my opinion, based on how it reacts to my listing, it looks like 100% is required to maintain the "%" ranking, but we do very few transactions here on this platform, so it's probably sensitive to this.
I don't know if this affects search placement as the discussion was solely about this new guest favorite at the time. The current search placement has 100s of data points that affect it and so I would think this could be relevant here as well, but I haven't come across anything via AIRBNB that indicates this either.