That's unfortunate, thank you for giving it a solid try!
My primary instance is stable, and the admin is quite able. I'd consider stepping up. I definitely don't want to be the only mod for any period of time. It's not just the time commitment, it's the implicit non-democratic status of the sub when one person makes all the mod calls. I'm @____@infosec.pub there, incidentally.
Edit: Went ahead and created it as a placeholder, pending any necessary further discussion or other volunteers here. !fountainpens@infosec.pub
Since content is instance-dependent, it might be nice to have a mirror on some other stable instance - not sure how to sync them so both get each others' posts, but don't duplicate though. This group in particular tends to have a lot of high-quality content and losing it is a blow - especially to noobs, who we actively want to be friendly and accessible to.
Is there a library for the API? Would be nice to seed a new community with some/all of the content here, if you don't object. Not like the reddit mirror bot posting a ton of things, but for initial content. Would prefer not to lose it all.