Google Sheets: How can I make the column dynamic in an indirect formula using the sum formula as well

I would like to use the INDIRECT formula to sum cells B3:B8 and any other rows I might add in the future. However, when I copy the formula the column don't change and it still reference column B.

Formula: =SUM(INDIRECT("B2:B"&row()-1))

I would like to make it so the column is dynamic and it changes to the appropriate column when I copy and paste.

For example, if I copy the formula to column C, I would like the formula to automatically be: =SUM(INDIRECT("C2:C"&row()-1)) without having to go and change the column manually.

Worksheet: https://docs.google.com/spreadsheets/d/1zYIevOm4638iWdIP3JhLf_5mPXd6VSS5gR0idkgaBRU/edit#gid=0

Is this possible?

Thanks for your help