I used Joomla 3, Joomla 4 and recently on my own projects Joomla 5.
I've had to reproduce whole websites from Joomla 3 to Joomla 4, so I worked with both side by side and Joomla 4 from a user interface standpoint is better way cleaner and more intuitive to do mostly anything.
As far as Joomla 5, it's basically just Joomla 4 really (I am sure there's some new stuff, but not noticeable). I actually think the Joomla 5 update came as a PR move, because Wordpress updates way more regularly and it's bad for a "direct competitor" to not update as often.
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TL;DR: Joomla 3 (less intuitive) , Joomla 4 = Joomla 5.