Use a metal backup to keep your seed phrase safe.

[JiiBs]

You won't have to use your finger nails to engrave metal plates by yourself or any tools for engraving made by yourself.

The manufacturers of those metal plates for wallet backups will provide a set of necessary tools for engraving, and you can do that by yourself at home, secretly, nobody knows what're engraving if you don't proactively share it on media.

• [Guide] Securing your seed phrase with washers.

Well, obviously you were not going to use your nails or teeth to engrave on a metal plate,

The link to the thread you provided had some really useful tools to the effect from what I can find. The jig and stamp tool does seem to be the most handy and easy to use. Just a hammer with an anvil and you would be good to go. It would all come down to how you chose to safeguard it afterwards because, having your seeds printed on a plate relays its importance.

[Stalker22]

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If you are looking for something more resistant to air and corrosion, stainless steel is not the best metal. Titanium offers more resistance than steel,

You catches my attention here...I don't know if you have forgotten iridium..it's the best metal resistance both air and corrosion...

Not sure iridium is a good choice here.  That metal is extremely difficult to machine and extremely rare.  If cost is not an issue, gold or platinum would be much better choices in my opinion (not to mention significantly cheaper than iridium).  Both are completely unreactive to oxygen, moisture, and air.

[Supreme Donvic]

You are not the first person who introduced this backup method and below are some threads in this forum as well as the big review post from Jameson Lopp with different tests.
Metal Bitcoin seed storage reviews.

Your 1st link is suspicious and seems risky so you should remove this form your post. once i clicked on your link it warn me as suspicious phishing link.

Writing the seed phrase on a metal plate is quite safe because it will not be damaged by water, rust or be thrown away if it is found in front of the family. However, the risk is that since it is a hard metal and the size is a bit large, if someone in the family ever finds it, they will be able to access the Bitcoin. The reason for this fear is that I do not trust anyone when it comes to Bitcoin security. However, if we can hide it carefully on our private locker, this weight will be safer than keeping an online backup.

Yeah, writing your seed phrase on metal is actually the best option I can think of right now, it is actually very safe and if you keep it in a safe place you won't have anything to complain about it.
If you see it as a valuable thing believe me you will find a place that you can keep it and no member of your family will be able to find it, except you are not good in hiding things in your house.
As I'm speaking to you right now my seed phrase is written on metal and hidden in my house, I'm very sure no one will be able to find it.