I do not see where the election to waive the carry back was made. There was nothing attached to the 2019 return.

It seems like we might need to amend 2019 so that we can do the following

1. Exclude the 2018 NOL from 2019

2. Include any portion of the 2018 NOL that could be carried back to 2019 (after carrying back to '13, '14, '15, '16, '17).

3. Include any portion of the 2020 NOL that could be carried back to 2019 (after carrying back to '15, '16, '17, '18).

I would also then be able to file form 1045 with the current year 2020 1040-NR to utilize the 2020 NOL beginning in year 2015 and up to 2018 since we would be amending 2019. 

Am I making things more complicated than need be? Any other way to fix this?

Yes, the client resides in another country but has US sourced income. They used to travel here frequently before COVID. Now they are working solely in their home country and looking to shut down all US entities.