The only way to secure bitcoin wallet is to create the private keys within a safe environment (a computer that has never connected to the internet, or at least, formatted the HDD and then installing an OS that never seen the internet). It's the only way. Then you must learn how to pass a transaction made on the offline computer within the online node. What can you do? it's the only way to go. Many find it annoying but it's what it is.

The main problem for me is passwords. I have bad memory, I always lose my passwords. I have lost access to all encrypted stuff because I lost the passwords.

As far as backups, im not sure about that. Putting your wallet on the internet doesn't seem like a good idea, even if encrypted... too paranoid. But also too paranoid to trust electrum seed's model. So what's the solution? Be careful to not burn your house or have thieves... I can't tell you anything else right now.