Better look on Linux?

[hadess]

I tried applying the following theme after installing ttkthemes with pip:

diff --git a/NiimPrintX/ui/main.py b/NiimPrintX/ui/main.py
index 390ff8dbbd8a..d9fdf9560a08 100644
--- a/NiimPrintX/ui/main.py
+++ b/NiimPrintX/ui/main.py
@@ -1,6 +1,7 @@
 import os
 import tkinter as tk
 from tkinter import ttk 
+import ttkthemes
 from tkinter import messagebox
 
 from .AppConfig import AppConfig
@@ -70,6 +71,9 @@ class LabelPrinterApp(tk.Tk):
         elif self.app_config.os_system == "Windows":
             style = ttk.Style(self)
             style.theme_use('xpnative')
+        else:
+            style = ttkthemes.ThemedStyle()
+            style.theme_use('yaru')
 
         self.create_widgets()
         self.create_menu()

but the UI looks like a mix'n'match of styles:

Is there a better way to get a more modern look on Linux?