I have been watching this forum today and have seen a lot of folks having troubles after modifying their Linux/Manjaro. Most of the problems seen to relating in modifying the main system. Linux is very permissive. This is good and bad.
My suggestions are:
If you want to experiment with Linux, install the distro twice in two different partitions. Call the first system your “Production Machine” and call the second system your “Test Machine”. Adopt this rule:
Aside from updates from your distro, never intervene manually. Then go wild, do anything on your Test Machine. That way you will always have a fully functioning system. When you make changes, document the change, oh yes, on a piece of paper. I have seen a number of threads in which the user cannot remember what they did.
Always back up your systems, especially the Test one.
Be an informed consumer! Before you manually modify your test system, research the change carefully. Implement one change at a time.