n = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141


we have our generaror as G in secp256k1:

G.x = 55066263022277343669578718895168534326250603453777594175500187360389116729240
G.y = 32670510020758816978083085130507043184471273380659243275938904335757337482424


now when I do :
res = G * (n-2)

result  is  -2*G but with negate y.


now lets :
generator is 2 as DLP:

when I will do with the same order:
pow(2,n-2,n)

I got resultat 57896044618658097711785492504343953926418782139537452191302581570759080747169

which is half point of G of secp256k1

why not n-2?