My question is, is there any best strategies a gambler can use to let a ball land on high multiplier in plinko game?
No.
Clarify me also if plinko is a game of luck. Thanks in advance.
It's not either.
What is usually called luck in this type of games is reduced to mathematical certainty. There is an unpredictability of outcomes in the short term, but a predictability of outcomes in the long term. I have explained about this in other posts, if you want to know more learn about the concepts of Mathematical Expectation and House Edge as well as statistics applied to gambling in general..