Oddbean new post about login | logout also note, you could flexible choose your security model and do 1/1 threshold with your own back up.. but then you still get the better uX of timeliness in case you need to migrate.
You’d still need to OTS it though since an attacker could do exactly the same with establishing the threshold. I don’t think you can get around requiring ordering if the source of truth is the key in question. That said, we have a pretty secure source of time ordering and OTSing is quite simple, cheap, and you only need to verify it under a very rare circumstance 🤷♂️