> Even if you simply have them written on a post-it note glued to your monitor people would have to physically break in your home to access them, which to me sounds like a very big additional layer of security for most people (as in: it won't happen unless you're a target for something big). Back them up to an off site (physical or digital) locations in case of a fire/flood/&c.
For me, the issue with this method is not so much on the security side but on that it is likely to fail when you need it the most. For instance, you are more likely to lose access to your 2FA device when traveling abroad than when staying home (e.g., smartphone breaks, gets stolen, etc).
> If that's how you see it then nothing is "safe". Memorising them ? Storing them in a physical bank safe ?
Having 2FA backups in the same password manager as your password would be pretty much the same as not having 2FA enabled, so why bother?
So far, it looks like a combination of two password managers from different providers seems like the most convenient option. Or Authy and not storing the backup codes.