If Id have really a lot of money in btc, I would store it in a hardware wallet and keep it in a safe place together with a piece of paper where the recovery phrase is written. I think this is the safest way.
The safest way to keep bitcoins is to store these bitcoins in cold storage where bitcoin will not be affected by hackers or any dangerous to them, I heard about some wallets namely trezor and ledger my friend told me that these wallets are really awesome and we need to save bitcoin there because of cold wallets property they have.
saving bitcoin in the market exchange is very risky because if the market closes then there is no guarantee you will get your bitcoin back. save in your server wallet will lose all your balance if you lose private key and such. storing bitcoin in cold storage is the best choice and I agree with your opinion.