After running the script, go to viewport,
ctrl + mouse_wheel_up: Resolution Scale + 0.1
ctrl + mouse_wheel_down: Resolution Scale - 0.1
(Go to keymap settings, make sure there are no shortcut conflicts)

import bpy
from bpy.utils import register_class, unregister_class

class SCALE_RES_UP(bpy.types.Operator):
    bl_idname = "view3d.scale_res_up"
    bl_label = "Resolution Scale Up"

    def invoke(self, context, event):
        bpy.context.preferences.view.ui_scale += 0.1
        return {'FINISHED'}

class SCALE_RES_DN(bpy.types.Operator):
    bl_idname = "view3d.scale_res_dn"
    bl_label = "Resolution Scale Down"

    def invoke(self, context, event):
        bpy.context.preferences.view.ui_scale -= 0.1
        return {'FINISHED'}

classes = (SCALE_RES_UP, SCALE_RES_DN)
addon_keymaps = []
def register():
    for cls in classes: register_class(cls)

    # Add the hotkey
    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='3D View', space_type='VIEW_3D')
        kmi = km.keymap_items.new("view3d.scale_res_up", type='WHEELUPMOUSE', value='PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))
        kmi = km.keymap_items.new("view3d.scale_res_dn", type='WHEELDOWNMOUSE', value='PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))

def unregister():
    for cls in classes: unregister_class(cls)

    # Remove the hotkey
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()

if __name__ == "__main__":
    register()

Example to make a script to add-on: How to duplicate parented objects as one object

After running the script, go to viewport,
ctrl + mouse_wheel_up: Resolution Scale + 0.1
ctrl + mouse_wheel_down: Resolution Scale - 0.1
(Go to keymap settings, make sure there are no shortcut conflicts)
(Scroll wheel shortcut doesn't work on Outliner, you need to change shortcut if using on Outliner)

import bpy
from bpy.utils import register_class, unregister_class

class SCALE_RES_UP(bpy.types.Operator):
    bl_idname = "view3d.scale_res_up"
    bl_label = "Resolution Scale Up"

    def invoke(self, context, event):
        try:
            bpy.context.preferences.view.ui_scale += 0.1
        except: pass
        return {'FINISHED'}

class SCALE_RES_DN(bpy.types.Operator):
    bl_idname = "view3d.scale_res_dn"
    bl_label = "Resolution Scale Down"

    def invoke(self, context, event):
        try:
            bpy.context.preferences.view.ui_scale -= 0.1
        except: pass
        return {'FINISHED'}

classes = (SCALE_RES_UP, SCALE_RES_DN)
addon_keymaps = []
def register():
    for cls in classes: register_class(cls)

    # Add the hotkey
    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='Screen')
        kmi = km.keymap_items.new("view3d.scale_res_up", type='WHEELUPMOUSE', value='PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))
        kmi = km.keymap_items.new("view3d.scale_res_dn", type='WHEELDOWNMOUSE', value='PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))

def unregister():
    for cls in classes: unregister_class(cls)

    # Remove the hotkey
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()

if __name__ == "__main__":
    register()

Example to make a script to add-on: How to duplicate parented objects as one object