Therefore, need to ensure that seed phrase is always with you. This gives you mobility and the advantage of not having to return to the locations where you left seed (this also creates the risk of being discovered by unauthorized persons). Life can be very unpredictable, and you never know whether you'll be able to return to the location with seed phrase stored (and whether your relatives and friends will be there to pass it on).

Accessing a cloud backup requires a login and password, which also need to be stored somewhere. If you forget or lose it, access to the backup will be lost.

I think if you use cloud storage, you need to complicate the storage process, meaning you need to make it difficult for unauthorized persons to access the data.

For example, you could pre-encrypt the encrypted seed phrase with a Caesar cipher or another known, accessible, or understandable method. This means that if attackers gain access to the cloud and decrypt your backup, they're faced with another level of protection.

Brainwallet + an encrypted seed phrase tattoo is also not the most secure method, but at the moment, I can't think of anything better. Tattooed skin is not the most durable material and is susceptible to injury. Damaging this area can also lead to the loss of part of the encrypted seed phrase. There's no perfect way to store the seed phrase. But in my opinion, the main advantage of this method is that the seed will always be with you, and no one but you will know about it.

Brainwallet alone is just as dangerous, because while intoxicated or delirious\in a dream, you can accidentally utter the seed phrase (although this sounds a bit paranoid, it can happen). Therefore, the seed phrase encrypted as a tattoo will protect even from you. In other words, it should be possible for you to "decode" it based on your tattoo, rather than memorize it.

This isn't a call to use this method, but rather a reflection on the best solution to this problem. In my opinion, having a tattoo "with meaning, like the seed phrase", is better than having a "meaningless" tattoo. This will have both aesthetic and practical benefits.

I also have another (slightly futuristic) idea for storing the seed phrase: implanting a capsule (not made of metal) under your skin containing information about the seed phrase. The problem I currently see is how to ensure that only you, and not someone else in a public place, can read the information in this capsule.

So, the idea is to always have the seed phrase with you (without anyone else knowing about it), allowing you to "decode" it at any time and use your wallet. The only question is how exactly to "add" the hidden seed phrase to your body so you can carry it with you at all times.

Don't suggest the option used in prisons.

Splitting the key into parts creates the problem of having to visit multiple locations, which can be difficult, for example, due to geopolitical situations.

Therefore, ideally, I believe, the keys should always be with you. The only problem is the method of implementing this.