"I actually have already read all of that"

And then you Apply it to each analysis.

"so then would you say that bonus depreciation is always the best answer?"

Facts and Circumstances matter. Let's say they already have a loss for 2020. Taking Bonus now means there is no depreciation expense that would help for the upcoming years. Or, they intend to sell it and quick turnover means they have to recapture the depreciation as income.

"The ones I find online show a large deduction the 1st year then no deduction for the next 4 years which I know is not right because proseries shows the 2nd year deduction is $13,703"

You need to go to the IRS, then. Notice in the links and articles that Tax year matters, that Temporary provisions might be in place. Pay attention to the date on the article, if it states it was recently updated, etc. Start with the IRS; they are the keepers of the Facts.