I don't think you really mean what you Said. That you want to keep your bitcoin safe forever,  meaning you really don't have plans for your bitcoin. And perhaps you dont have an investment plan or Target, like how long your investment will last or whether you will still be accumulating. It's seems you just want to be stocked with what you have. Very funny of you.

For the electron wallet I see no wrong about it. It's a person choice to choose any type of wallet of your choice but when choosing be security concious. For the Cex you said I think it's  better you save your coin in DEX rather CEX.