Remembering or memorizing your seed phrase would never be recommended, it may be easy to remember 12 words in the first few days, weeks or months, but in years and with many other things that the brain accumulates as time passes, you can easily forget some words or the sequence. With good OPSEC nobody is going to find your seed phrase written on paper, just back it up properly. The brain is fragile, and if one stores 12 words or more in their head, then with just a brain disease or injury, their BTC could be gone, it is better and safer for it to be on paper and in two different locations.
I agree with that, sometimes it could be not only 12 but 24 words (BIP39), and it's pretty hard to remember constantly, even for a young age person. I would definitely not recommend just memorizing it and keeping it in your mind. As you said, you could even forget the sequence one day or get a brain injury that would make you forget it.
I mean, it would be extra for you if you remember it in your mind as 2FA (which is really good), but it's better for you to keep it safe somewhere, like on a piece of paper or by engraving it on steel or a stone that won't break, and hiding it in a place that only you can reach. Just think of it as your identity or your passport, or even more important than that if you have a lot of money in your wallet, because it can't be recovered.
My biggest
recommendations are:
1. Not to save it on your PC or any device connected to the internet, that's a way too risky.
2. Store your seed phrase 2-3 times in different places and make sure it won't get damaged even in a disaster + (bonus if you have it memorized in your mind)
3. Don't leave any obvious hints about your seed phrase to any of your friends. However, it's probably a good idea to give a hint to at least 2 members of your family (in case you die) so your bitcoins won't be lost.