The normal ticket gate behavior in Japan is that when you enter, the gate gives you the ticket back so that you can carry it all the way to the exit in order to prove that you traveled that journey. When you go through a ticket gate to exit the station, all Japanese ticket gates to my knowledge will dispose of your ticket.
I retained approximately one ticket in Japan. It was due to walking through a transfer exit gate at some station of the Tokyo Metro, which lets you walk through a non-fare-paid area to re-enter another station.
I also retained all the Shinkansen seat reservation tickets (特急券) back when I had the old-style JR Pass, where you always had to enter/exit stations with help from the station attendant - and not use automatic ticket gates. I haven't tried the current style of JR Pass (since maybe 2022?), but I imagine that the exit gate would eat your seat reservation ticket, just like if you had bought the ticket in cash.
