None of these other methods will work. Even a person with the strongest willpower might one day want to sell their Bitcoin. That's why if you want to hold your Bitcoin long-term, send it to the wallet of someone you trust and agree not to get it back before a certain period. Another alternative is to send it to an address you created, store the key on a flash drive and put that drive somewhere you can't easily access. After a certain period, you can go there and get it back.
There's no other way. If your Bitcoin is somewhere you can reach easily, there's always a chance you won't be able to resist selling it.
Transferring Bitcoin to a person you rely on is more appalling than using a centralized exchange is because you lose full control and your made vulnerable to credit risks. Multisig is an advanced, correctly configured to 2 of 3 or 3 of 5 wallets and distributes your keys all over your hardware wallet and parties you believe in so not a single person can drain funds alone. I know, it makes entry more complex but increases your security. Instead of surrendering to bitcoin control, safe returns via income diversity and depend on reinforcement, not just believing others won't panic and sell.