I'm on Safari 16.2 on macOS Ventura 13.1 (Beta 2), but this issue has been ongoing since before then.
When I first started seeing the Iframely "Can we show you third party media" boxes on Cohost a few months ago, I clicked on the "Settings" box and ticked the "Trust all media providers on cohost.org" box. In general, though, it seems that this doesn't work.
On the Iframe itself on an individual cohost post, the "Always for <service>" sometimes will work for a few hours, within that tab only, but later on the question will always come back.
I have not spent a lot of time playing with cohost, especially this feature, on other browsers, so I don't know if it's also broken there.
Similar problem. For example, on posts like this one:
I have tried both the "always for..." button on the post, and the settings in the settings link, and my preferences do not seem to be saved.
I experience this on iOS Safari, MacOS (Safari, Firefox), and Win 11 (Firefox), but it seems like the sort of thing that wouldn't be browser or eve OS dependent. I feel like I've tried Twitch, YouTube, and Twitter third party media.