Given that this thread is in the Beginners and Help forum, the whole topic could be condensed as follows:
Write it down on paper, make at least two copies, and store them safely and separately.
That's it.
That's right because most of the newbies here don't have any idea about using different ways to store their seed safely and in that case the perfect advice is to store them safely on piece of paper only without any online storage involvement.They should note it down once they have setup their wallet and no pictures should be taken or saved as notes in the mobile phone which could be reason for loss of funds.Having proper backup in two or more places is important because if one place is compromised you can have it from other sources.
You cam trust someone close to you in case something happens to you they can use your funds but keep in mind trust is the vital factor that plays major role in keeping your funds safe.
Splitting your seed phrase or obfuscating it with swapped words or order is always a bad idea. It very rarely increases your security in a meaningful way, and more often simply leads to problems recovering your coins in the future. If you want to have a 2-factor back up, then use passphrases or multisig.
Mixing up the words maybe confusing for the person himself and he needs to sort the words in order to use his funds or transfer them but in the case of splitting it becomes more difficult as you have to collect the words and if any of the 12 or 24 words is not in correct order or not available with you then funds are lost permanently.So why go with such complex methods when you some simple and traditional way can save you from lot of troubles.
Memorizing your seed phrase is a terrible idea and should be practiced by no one.
I remember there was one such thread on the forum where member was using unique way of memorising the seed phrase like with images of Queen Elizabeth, elephant and relevant example but it sounds too complex and bad idea to many including me as human mind is strong and can have storage but there are some limitations and we should not experiment with them in such risky way.So avoid this is really bad way of keeping it safe as it this could direct lead to fund loss.
Other than writing on paper, the only other item on that list which is acceptable is a metal back up. However, this is by no means necessary since paper is a perfectly adequate back up, and metal back ups require far more time and effort than writing on paper. There is no need to get hung up on making a metal back up instead of just making paper back ups and converting to metal at a later time.
You can try different methods other than paper definitely but it's time consuming and you need to have proper metal that can survive extensive condition of heat also so that in any case of calamity or fire it could survive the damage with seed backup safely printed on it.Members could take a look at these threads:
Securing Your Seed Phrase with Washersn0nce's Steel Washer Backup jig (customisable)There are many such ways in which you can protect your funds but see they all are offline ways because storing them in online storage like cloud,drives or even having them stored on your device as soft copy is prone to hacks and stealing of your funds so be safe not to use them and keep your funds safe because it's your responsibility.