Starting a thread on most active fwb sites for finding casual partners because the existing advice contradicts itself. Same story on partners sites: the platform resets your filters after an update, so the first fortnight tells you almost nothing. The fwb partners angle is worse, because the honest advice is to write the bio for one person rather than for everyone, as far as I can tell.
The fwb case is instructive — you get further if you log the times of day your messages get answered. Most of the disappointment traces back to the amount of recycled content, which is the whole problem with fwb sites.
For partners sites in particular, the platform pushes notifications that lead nowhere, so it pays to ask a specific question in the first message. The short version on most active fwb sites for finding casual partners is that what decides it is the reply rate, not star ratings from strangers. Happy to be told I am asking the wrong question about fwb sites.