This does not apply to CTRL-SHIFT-F search, which already defaults to order by date.
If the latest version hasn't yet appeared here, you can always download it at http://lacinato.com/cm/software/extensions/srsbdnr
This is the bug that covers this issue: https://bugzilla.mozilla.org/show_bug.cgi?id=663859
Many people have requested that this add-on also make "open email as list" the default for search results. This is not a simple thing to do, and I probably won't be adding it here any time soon. I would refer you to the add-on "Search as list" which unfortunately has not been updated past v60. That developer does occasionally update it, though, so I'd recommend contacting them and begging nicely, perhaps with a generous donation in hand: https://addons.thunderbird.net/en-US/thunderbird/addon/search-as-list/?src=search
You might also post your requests at https://discourse.mozilla.org/c/thunderbird/
An experienced developer probably wouldn't have too much trouble updating the Search as List add-on for recent versions. Both this add-on and Search as List could also be integrated into the base code, which would be great, and probably not much work. Considering how many users this plugin has, I think it would be appreciated by a lot of people.
If you have any trouble please contact me through the homepage for this webpage: http://lacinato.com/cm/software/extensions/srsbdnr