How to get 1 billion coins per run?

So em I started about 2 months ago, currently averaging 1.5k wave at T1 earning about 1.5mil coins per run.

Getting a billion per run seems amazing.

What do you need to unlock to beat past the strong enemies around 2000 wave? I can’t even reach 1.7k hahaha

Please do share your wisdom dear old timers and don’t use jargons I’m sorry I’m too new in this game 🐬

Reason I’m asking is because I see the 997mil upgrade which seems so hefty and unreachable but seems so doable in the community with runs reaching 20T per run reading some of the posts here