Generally speaking, Soul Masters can only use Soul Guidance Devices of the same level unless there is a special technique involved in the making, or the Soul Guidance Device itself has unique properties that allow for its use across different levels.
How old is Meng Hongchen? Possessing the cultivation of a Soul King at such an age is already incredibly rare, and without asking, one can deduce how much effort the Sun Moon Imperial Soul Master Academy has invested in her. Her cultivation is almost certainly not achieved solely through her own abilities, especially since she is also training to become a Soul Guidance Master.
Even now, with Huo Yuhao possessing Twin Martial Souls and the support from the three great powers within him – the Skydream Iceworm, the Ice Empress, and Alex – he still couldn't reach level 50 Soul Power and become a Level 5 Soul Guidance Master before the age of fifteen!
