#include <bit> // byteswap, endian::native/little
#include <concepts> // integral
#include <type_traits> // has_unique_object_representations_v

namespace std {
    template<std::integral T>
    constexpr T ntoh(T const value) noexcept
    {
        static_assert(std::has_unique_object_representations_v<T>,
                    "T may not have padding bits");

        if constexpr ( std::endian::native == std::endian::big ) return value;
        else return std::byteswap<T>(value);
    }

    template<std::integral T> constexpr T hton(T const value) noexcept
{ return ntoh<T>(value); }
}

Although personally I'd be more comfortable for the parameter to be
std::type_identity_t<T> so that you have to explicitly specify the
type:

        cout << "Number: " << ntoh<uint16_t>(65029) << endl;