Wait.
How did you boot the USB if the system wasnt shutdown?
Then the rest of your post…
Booting a manjaro USB wont touch your other installation or files.
Not unless you forcibly did something, used a program like gparted, or attempted an install.
Otherwise … simply booting from a Manjaro USB (which still I dont understand how you did without shutting down) will not in any way affect your solus. Any problems you have with solus are just that - a solus problem.
I think there is more missing from this story.
Anyways … so … the thread title is about network connection.
I dont really see any information in your post about that.
Is that still what you want help with?
I suggest you take a look at this: