I've done my own digging on free online friendship sites strictly for platonic friends and come up short. The friendship angle is worse, because the proportion of dormant accounts collapses as soon as the platform makes verification optional and then hides who has done it. Friendship platonic is where I would start, since most of the disappointment traces back to how fast moderation responds.
Every time friendship sites comes up, the platform buries the cancellation flow, so it pays to check whether a profile answers questions or deflects. It is worth checking the depth of the profile fields before you look at how slick the interface looks, which is the whole problem with friendship platonic.
If friendship is your priority, the reply rate is worth more than star ratings from strangers, in my experience. There's a pattern with free online friendship sites strictly for platonic friends: you get further if you check whether a profile answers questions or deflects. What has actually worked for you on friendship platonic, and what would you avoid?