Yeah, it's sadly predictable that OP is seeing this play out in the workplace. People who cheat to get hired are also likely to scheme and manipulate their way up the corporate ladder. This happens at almost every company, every day.
Interestingly it doesn't have to be this way. This is mostly due to the fact that nearly all companies use a command-and-control management structure where people are promoted by the people above them. Stealing credit from your co-workers and/or convincing your manager that you're going to support them is a surefire way to climb the ladder.
The solution is simple: promote from below.
Basically, teams should be lead by people they have democratically chosen, and that process should continue all the way to the top. I've always found it curious that most of the world recognizes democracy as the most effective way to structure a government, but the corporate world is obsessed with dictatorial command-and-control structure - with predictable results.
Disclaimer: I am the co-founder of a co-op dev studio that was based on 18th century pirate charters (https://www.fountstudio.com/blog/yes-we-have-a-pirate-code-1...).