honestly? it's one of the best ending for a series like this, I don't like Yuragi Sou Yuuna san's and we never learn tactic because it feels insincere, I prefer things to be tied up in such a nice knot like this.
This is also much, much, much muchmuchmuch better executed than nisekoi (which IMO is such a more inferior, aimed at younger crowd romcom) and Domestic na Kanojo (feel like trying too hard to be 'adult' oriented while feels flat compared to this)
Id much rather when they actually take a clear stance, whether it's to choose one girl OR just take them all. the Yuuna and never learn one is a cop out where the author doesn't want to write anything complicated and want to lengthen his pay job just a bit longer.
in the end if I ever want to have the other girls' route (of which I always jumps between Miku, Nino and Itsuki) id write a fanfic of them myself anyway. 😏