MD5 is computationally fast. This is great for routers checking your login, but it is also great for hackers with modern GPUs. A modern graphics card can try billions of MD5 combinations per second. A weak password hashed with Type 5 can be cracked in minutes or seconds.
I have some bad news for you:
Unlike Type 7 passwords, which use a weak Vigenère cipher that is trivially reversible, Type 5 uses the algorithm. How to generate cisco key-hash string cisco enable secret 5 decrypt
The immediate internet search that follows is: “cisco enable secret 5 decrypt.” MD5 is computationally fast