I've some questions about Ghidra released by NSA on Github. And research about it then saw a ycombinator thread for it. That answer was clever and funny.
As title marked, you really okay for just "open source" to trust it?
Ghidra is used by the best and brightest malware inspectors. If it was backdoored, it would have been discovered almost immediately.
The NSA has two conflicting missions, one is to hack everyone, and the other is to protect American networks and interests. Ghidra is from the later, its goal was to make malware analysis cheap and accessible so that more people can investigate and defeat malware.