@aero1016 ,
Go to "Edit > Preferences > Tools > Tool paths" and make sure the "Terminal" field contains the following:
cmd.exe /Q /C %c
Hitting `F5` should launch the legacy Command Prompt (white on black text, no theme colours, no UTF-16 encoding):
Geany 1.36 Windows 10.0.22000.588 Windows Terminal Version: 1.11.3471.0