Feature request: more detailed explnanation on preffared way declaring global constants

Consider we have Consts.h, where we want to declare some defaults used across application. (very)Old way where macros, now we have constexpr. BUT, there's multiple variations of that, and I personally feel confused on what to use.

For example, https://www.learncpp.com/cpp-tutorial/const-constexpr-and-symbolic-constants/ suggests to use inline constexpr since C++17 (without arguments on why), and you can find StackOverflow discussions on how static constexpr variables will be initialized once per application (which might be "better"?), if I understood correctly.

So, current possibilities:

Consts.h

#include <chrono>

namespace consts {

    constexpr auto DefaultTimeout1 {std::chrono::seconds{1}};
    static constexpr auto DefaultTimeout2 {std::chrono::seconds{1}};
    inline constexpr auto DefaultTimeout3 {std::chrono::seconds{1}}; // since C++17?

};

So.. when do we use which?