the console of the windows os is not working in the utf-8 encoding, by default. When you force your code be encoded with utf-8, the console will not print what you want.
Here is how to configure your project encoding with utf-8, and work as it is in windows.

configure visual sutdio to encoding with utf-8

add a .editorconfig file to you project. visual studio will use the encoding as the configuration file asked.

put the code in the .editorconfig

# Rules in this file were initially inferred by Visual Studio IntelliCode from the D:/data/playGround/playGround_y9kp/playGround_y9kp/ codebase based on best match to current usage at 2022/8/27
# You can modify the rules from these initially generated values to suit your own policies
# You can learn more about editorconfig here: https://docs.microsoft.com/en-us/visualstudio/ide/editorconfig-code-style-settings-reference
# [*.cs]

[*.{js,py,cpp, hpp, c, h}]
charset = utf-8

set your project build and execute in utf-8

this will be configured in the project property page.

tell the working encoding at the very beginning of you code

int main(int argc, char** argv)
{
    system("chcp 65001"); // set the console work with utf-8 encoding.
    cout << "aaaaaaaaaa" << endl;
    cout << "噫吁戏危乎高哉" << endl;
    cout << "aaaaaaaaaa" << endl;
    return 0;
}

start to run you code and check the result