Missed QBI deduction for 2018 and need to amend, should I wait to file 2019?

I missed my QBI deduction for 2018 somehow, which means a huge difference in my business deductions. I also did not realize I needed to file in several states that I did work on-site in.

 

I'm going to amend 2018 which will result in a large refund from Fed and my home state as well as several smaller non-resident payments to other states.

 

I'm trying to figure out what order I need to file these in. If I file 2019 right now and amend 2018 later, will I also need to amend 2019? Do I amend 2018 and adjust the numbers from 2018 on my 2019 taxes?

 

Thank you!