Have you tried Move Window to the next monitor action? In my case, I've set it up to work on FN + arrow UP / arrow DOWN, and attached additional action to just go into fullscreen mode ( i mean, fill the remaining space, not go into the native fullscreen mode) in my setup. But you could attach any other additional action and resize the window as much as you want, I suppose...
Here's a JSON of my Trigger:
{
"BTTGestureNotes" : "Move to next monitor",
"BTTTriggerClass" : "BTTTriggerTypeKeyboardShortcut",
"BTTPredefinedActionType" : 47,
"BTTPredefinedActionName" : "Move Window to Next Monitor",
"BTTAdditionalConfiguration" : "8388608",
"BTTEnabled2" : 1,
"BTTUUID" : "0626528B-A6DB-4AA5-A35C-6DBB8AFA65AA",
"BTTEnabled" : 1,
"BTTShortcutKeyCode" : 116,
"BTTShortcutModifierKeys" : 8388608,
"BTTOrder" : 26,
"BTTAdditionalActions" : [
{
"BTTTriggerType" : -1,
"BTTTriggerClass" : "BTTTriggerTypeKeyboardShortcut",
"BTTPredefinedActionType" : 129,
"BTTPredefinedActionName" : "Delay Next Action",
"BTTDelayNextActionBy" : "0.108415",
"BTTEnabled2" : 1,
"BTTUUID" : "BB5939D5-9E1E-43E8-B8A3-F2676F5AA12F",
"BTTEnabled" : 1,
"BTTShortcutKeyCode" : -1,
"BTTShortcutModifierKeys" : -1,
"BTTOrder" : 0,
"BTTIconData" : "",
"BTTAlternateIconData" : ""
},
{
"BTTTriggerType" : -1,
"BTTTriggerClass" : "BTTTriggerTypeKeyboardShortcut",
"BTTPredefinedActionType" : -1,
"BTTPredefinedActionName" : "No Action",
"BTTShortcutToSend" : "58,55,3",
"BTTEnabled2" : 1,
"BTTUUID" : "73A6D6B8-06A3-4C8A-A6CA-BD89DCEEE7F9",
"BTTEnabled" : 1,
"BTTShortcutKeyCode" : -1,
"BTTShortcutModifierKeys" : -1,
"BTTOrder" : 1,
"BTTIconData" : "",
"BTTAlternateIconData" : ""
}
],
"BTTIconData" : "",
"BTTAlternateIconData" : ""
}```