these "words" are actually representing the "entropy" that is used to generate the individual private keys. so unless you can come up with a way to generate the same level of security entropy (at least 128-bits) using 3 words, it won't work.
You can do it using
https://iancoleman.io/bip39/ and i understand you wont achieve 128 bits, this is where the passphrase with strong password is extremely important.
are you really suggesting that memorizing 3 words + something like
J\{m^"<Aw2ATdn)V96
is easier than memorizing this:
legal winner thank year wave sausage worth useful legal winner thank yellow
i'm not convinced!
No, i am not suggesting to create your password like this. you can create something like !Went>P@r!$&be$tmem0ryev_r
Something that you can create that reflect to your experience and easy to remember and hard to crack