"They were installed in 2018 but never put down to write off."

That's not how to determine when something gets reported. Neither is "every year I pay for it."

The significant tangible item is what qualifies or not. The regulations use "placed in service" and or "completed" for the determination. If you install something in 2018, but it is not inspected and approved for use until 2020, you would have something that was "placed in service" in 2020.

"Taxpayer is now doing 2020 and 2021 taxes so always behind"

You don't get to save things and use them in the tax year most advantageous for you. You use them in the tax year to which they apply.