I’m no lawyer either. I have been involved in similar cases at tech companies though (on both sides).
Copying PUBG’s map shrinking mechanic doesn’t seem actionable to me alone. There is strong intent and “inspiration” from many games.
If there was intent to copy and opportunity to use something covered by implied or explicit non-disclosure agreements then that’s something. For example, if EPIC had access to information due to being in a separate license agreement for their engine and used that information to go-to-market quicker.
The other thing that makes action difficult is proving damages. For example, Discord is essentially (or almost literally) Slack marketed to a different demographic (gamers). It is basically the same software. To take action though, Slack would have to prove that there are damages incurred by Discord existing in the market.
If they really dig I’m sure they could find some gamers who used Slack and now use Discord, or some data that shows there is confusion in the market when a gamer sets out to choose a platform for chatting with a group. It’s so hard though it’s generally not worth it.
The better use of that money is to work on making something better for the consumer and simply out pace the competition that is ripping you off. Or acquire them if you have the cash, of course.
That’s what PU should be focused on, in my opinion.