I can confirm it is annoying (In reply to alta88 from comment #4)
...it's not something we can reasonably change.
This isn't true at all. See Bug 1669872.
@fop - all you have to do is go to Preferences:General and toggle the "Show only display name.." checkbox to cause the database to be refreshed. For a large folder, particularly if sorted by From, it may be slower entering the folder for the first time, but not nearly as slow as before Bug 1669872 (and it could be made ever more performant). If you also want to use the display name in a Quick Filter search for email type textfilters (Bug 460737), see TotalQuickFilter.
This method works with thunderbird 68 & ubuntu 20.04, but not with 91.1.0 and Win10 : in this case, unchecking "Show only display name.." makes a blank page and nothing change at restart.