This is only true if all the wallets you intend using are open source and are in a safe device, otherwise you would only be giving yourself a false sense of security. One cold wallet that is properly backed up is much better than so many closed source wallets in different online devices that are used to access anything over the internet.

If you also struggle to find a safe location to keep your backups, you should consider reducing the number of wallets you have, so that you have less seed phrases to back up securely.