There would be plenty of options available once you're thinking "outside of the box"

How about a lounge for long-hours transit pax, possibly in T1? The space from the Thai lounge has become available, for example. Low-service, "quiet" place with less offers, just to handle the overflow, especially designed for pax with long transit hours who want to stay airside.

How about "grab&go" packs for pax nearby the entrance that just want a quick snack/are in a hurry, and won't mind eating at the gate? Including a "take away" drinks corner at the gate (after security, on the side where they get their BP scanned, so it wouldn't require extra staff..) for C/*G pax? Dabao it!