You are thinking in hard way.

Forget about the USD price, you dont need it.

Simply consider that:
Cost of hardware + cost of electricity*time / BTC production

Considering:
- 150 EH/s of hashrate growing at 145 PH/s per day.
- 144 blocks per day.
- fee reward is not included.
- 6.25 BTC block subsidy.
- 100 TH/s, one miner.
- 3250 W power consuption.
- 8000 USD cost of hardware.

This give you a graph like this:


*Where Y axis is Price in USD and X axis is days passed since start of mining

When this curve will be UP related to Bitcoin price, then mining will be profitable.



As you could see, mining allow you to obtain BTC at a price below to 50k for almost 10 years.