In the end, it depends on several factors, like what stack we are talking about and how comfortable you feel with it.

But generally speaking, I would chose one super cold wallet with the main holdings. If it is set up right (air-gapped, self created entropy) and the seed secured right (indestructible and safe) and ideally stored on your brain, I can’t really think of why multiple wallets would be better. Chose a 24 word seed and the entropy is so huge, that there is not a real difference whether you chose one or two seeds. Backup needs to be solid though. Steel backup put in a safe or somewhere hidden REALLY good should keep you safe.