As Fallout said you need to manually assign buttons, WT doesn't have premade mappings for it.
That being said do keep in mind that War Thunder can be troublesome as it has a limit of 256 buttons in total across all connected USB game controllers. That's not 256 buttons per device, that's in total.
If you have several controllers plugged into your computer - especially VKB devices which by default list 128 logical buttons each- it is possible to go over that limit very quickly. War Thunder enumerates POV outputs *after* the regular logical buttons, which means that for the Gladiator, which lists 128 buttons, the POV outputs will be buttons 129-132 on that joystick. If the Gladiator isn't the first device listed by WT, it's entirely possible for the POV to be unrecognized by the game because it goes over the limit.
If you cannot manually assign your POV in game, you are likely to have hit that limit. The solution is to disconnect all unused USB controllers and/or to reduce the number of buttons exposed by VKB devices in vkbdevcfg using the #But field in Global > Common until you total - including POVs - falls beneath the limit. You may also reshuffle the logical button assignments in vkbdevcfg to make sure the buttons you care about are listed first, in case you must make sacrifices.
Your War Thunder mappings files are in
Each .BLK file contains a
deviceMapping section which lists the devices recognized by this mapping, and the number of buttons and axes exposed by this device. If the sum of all the
buttonsCount entries for connected devices exceeds 256, some of your buttons will not be recognized by the game. Manual changes made to the file in this section are ignored by the game.