Two should be enough in my opinion. One of storing and one for recovering in case something happens to the first device.
Don't use wallets like Jaxx and Exodus, they are not open source, you never know what's going behind the scenes and If they have access to your funds or not.
Store everything in one device, write the seed down in multiple pieces of papers and hide them in different locations. If the hardware wallet gets lose or damaged, you could use the seed to recover your coins.
the higher the number of time the seeds are written down and kept in multiple places, the greater the chance of losing the coin to third party. Holding such huge amount of money is like holding something that when you lose it you are going to lose your life. I have seen people keeping valuable assets in banks and other third-party. putting hardware wallet that contain such amount of money in bank is not a bad idea. Even if the owner died, I am sure his/her family will still have opportunity to make use of the asset. my own opinion though.