Does memory of such C++ that can be used in debug build exists somewhere? Yeah, one can still write that. Example from open source:

    tracy_force_inline void swap( Vector& other )
    {
        uint8_t tmp[sizeof( Vector<T> )];
        memcpy( (char*)tmp, &other, sizeof( Vector<T> ) );
        memcpy( (char*)&other, this, sizeof( Vector<T> ) );
        memcpy( (char*)this, tmp, sizeof( Vector<T> ) );
    }

This is quite fast in debug.

Will people who write C++ in 202x gamedev do it? Nah, I don't think so. Just stop even maintaining that pesky 'Debug' build and it will be fine. Build configurations grow in other direction. There are optimized configurations already that do not need local build step - LTO/PGO and friends. People just do not build that locally and real world performance is there.

YMMV of course.