I'm not sure, but I think I see two things that may be helpful.

1) It seems that the messages in your screenshot are grouped by sort. If you sorted by "threaded" instead, messages in a thread would be sorted in chronological order, so the latest message would be the last one in the list. If you don't sort by "threaded", you are not really using threads. You seem to be organizing messages by subject instead of by thread. Is that right?

2) Your screenshot shows only "Thursday" for date and time. I don't know why. My messages always have date and time. Maybe information here will help you change "Thursday" to date and time so that you can compare times visually. https://support.mozilla.org/en-US/kb/customize-date-time-formats-thunderbird

thanks. Grouping and sorting in Thunderbird is not very intuitive. See my settings attached

Sorting by subject sounds to me like trouble, just by definition. Often the subject of a thread changes mid thread and getting related information together is about the last thing it would achieve. Sort by date works for threading quite well and older threads are promoted in the date list to the position the last email in the topic would have occupied. They may bring exceedingly old email along as context, but the date of the last email in the thread dictates the threads location.

Add to that Thunderbird does not really thread as part of the sorting (despite recent user interface moves to make it look like a sorting thing) and you may start to understand why you think sorting is not intuitive.

Thunderbird threads mail by default. So if it is not happening, turn it on in settings. But that list you posted is sorted by thread.

Threading is a complex subject in it's own right, as there are many email users without any email skills at all. They do things like find the last email they sent to someone/list and then forward it again after removing the content to make it new. Except that email retains it's ID and threading uses it. So mail from these folk tend to turn up in long closed threads years after the last email.

This talk of groupby sorting really looses me. Essentially it is best used to "age" the lists by grouping by date so you get a Micrisiftesque Outlook list.

like this

What I would strongly recommend is you dump the Card view for the table view of your email as it shows indents in Threads that makes working out who is replying to whom and in what order much easier that the bland cards which consume line after line for each email and offer essentially nothing in return that is also available on the single line table view.

Table view Card View

It also means you can dispense with the selecting of the whole list like you obviously are to get the summary view in the reading pane. It took me a whi8le to recognize that when you posted it.

This talk of groupby sorting really looses me.

Just an observation that Johannes seemed to be using it because it helped me reproduce their view.