Are you calling these using python or C++ ?
When I run the code below they all return the same wx.App object.
I am using Python 3.10.12 + wxPython 4.2.1 gtk3 (phoenix) wxWidgets 3.2.2.1 on Linux Mint 21.2
import wx
app = wx.App()
print(app)
print(wx.GetApp())
print(wx.App.Get())
print(wx.App.GetInstance())
print(wx.AppConsole.GetInstance())
Output:
/usr/bin/python3.10 /home/richardt/Development/python/exp/hci/wxpython/app/app_exp_1.py
<wx.core.App object at 0x7f677992bd90>
<wx.core.App object at 0x7f677992bd90>
<wx.core.App object at 0x7f677992bd90>
<wx.core.App object at 0x7f677992bd90>
<wx.core.App object at 0x7f677992bd90>
I just use wx.GetApp() in my own python code.