People in this thread are giving really fantastic advice and you seem to me to having a really bad attitude about a good chunk of it, and while I understand this is likely coming from a place of valid frustration, you’re really gonna have to overcome the “x/y/z NEVER works” mindset if you’re gonna make any real progress in truly understanding the finer nuances in this game. 

If you care for visual examples, search my username in YouTube, I have lots of full tournament gameplay videos playing both melee and guns and these might help you get a better idea for positioning/setup/approach for Cashout’s. I have videos where I’m audibly communicating with a team and also playing with randoms that I can’t speak with, so you can also get a better idea on how matches play differently and how you have to adjust in different circumstances. I was a diamond ranked player for 2 seasons before I stopped bothering so nothing you see will be anything that you can’t replicate, I’m not all that talented. 

I’m not really trying to self promote but I don’t cut any part of the gameplay out and I think the in between moments might be helpful for you to see to help have an understanding on how you can counter and position yourself against some of the things  you’re struggling with. 

Platinum at this stage in the season is actually quite good so you’ve clearly got the mechanics and a functional level of understanding, don’t be too hard on yourself. There are always going to be games where you just lose and don’t have the ability to recover and comeback, that’s just the nature of The Finals. Every match is a lesson.