self.option_var and self.option_buttons: tk.StringVar is used to hold the selected radio button's value. A loop creates four tk.Radiobutton widgets, each associated with option_var. self.button_frame: ...

Is it laggy? That's ok. Tkinter isn't built for applications like this - ones that involve lots of constant updates. It's designed for simple GUIs with buttons, entry fields, etc., to get user input, ...