The whole point of docker is to solve the “work on my computer” by providing the developer hacked up OS with the app. (Rather than fixing it and dealing dependencies like a grown up)
Bit special for it to still be broken. If it flat out doesn’t work, at all, then it may well be “sunk cost fallacy” to keep working on it. There is no universal answer, but there is a developer tendency to rewrite.
Sounds like you were given a mess alright.