I just came back to the game after not playing for like 5+ years and I want to make easy gold so I am going to buy a bunch of platinum.

I want to know the best way to make gold with platinum. Should I buy forgotten elixirs for 10 plat and sell them for 400k each? Should I buy 50 crate keys and sell them for 3m? Should I buy the forerunner sets in store if I can? Are there better ways to make a lot of gold with platinum that I dont know about?

Thanks.