Terrible idea. It might work right now but as @anon51566685 says you will end up with a broken system in the not too distant future.
If valgrind is an essential daily requirement for you then unfortunately Manjaro is not the solution. Even on unstable branch it will break sometimes as you’ve seen, and the only way that will ever change is if Manjaro provides their own debuginfod server instead of using the Arch Linux one. Use Arch itself or some other distro that provides that - elfutils debuginfod services