The only positive thing I ever heard about lemmy.one is that they federate with Beehaw. At the time I was already skeptical of that being a good thing since Beehaw has harsh opinions on moderation and had already said they wished to exit the Fediverse. So I dismissed lemmy.one back then as being one of those unremarkable and poorly managed instances, and it seems I was largely right. It is still sad to see an instance leave like this.