I don't know if the following will be of any help, but since it's in my stash of tutorials, it can't hurt:
Rearranging the Column Order in Thunderbird Using the NVDA Mozilla Apps Enhancement Add-On
The following presumes you have already installed the previously noted Mozilla Apps Enhancements add on, have restarted NVDA, and have Thunderbird up and running with focus on the Thunderbird window.
1. Hit NVDA+H. A dialog entitled, Manage columns, appears. That dialog is composed of a list of the columns in the order they are currently being displayed from left to right, with the leftmost column at the top of the list.
2. The next thing I suggest you do, but this step is optional, is to hit ALT+O, which will cause the list of Thunderbird columns, in Thunderbird itself, to be displayed with a checkbox in front of those columns you wish to have displayed, and nothing (unchecked) for those you want to hide. It's worth down arrowing through that column list and deciding if there are any currently checked (displayed) columns you'd like to hide, and uncheck those, and vice versa. Hitting ESC closes the Thunderbird column selection process and throws you back to the Mozilla Apps Enhancements dialog.
3. Back in the dialog column list, gain focus on the column that you would like to move. If you want it to be to the left of where it is (and that means it would be announced first), then hit ALT+U to move it up by one position. Repeat the ALT+U as many times as necessary to get it where you want it. If you want this column to be announced later than it currently is (moving it to the right/down the list), hit ALT+D as many times as necessary to get it where you want it relative to other columns.
4. Review your column order by going to the top of the list and down arrowing through it so you know what the "First announced to last announced" order is. If you find a mistake, then repeat step 3, moving the column or columns to where you want them.
5. Navigate to the Close button for the dialog and activate it. You're done.
Brian - Windows 10, 64-Bit, Version 21H2, Build 19044
The real art of conversation is not only to say the right thing in the right place but to leave unsaid the wrong thing at the tempting moment.
~ Dorothy Nevill