XAPK is a zip file. I will show you how to extract OBB file directoy to OBB location
Use file manager like X-plore that supporting opening XAPK as a zip file. On Android 11 and above, please check this guide how to access obb folder
Open the XAPK file directly as ZIP
Copy the OBB files from /Android/obb to /storage/emulated/0/Android/obb/(package name)/.
On Android 11 and above, if the folder of the package name of the game does not exist, do not copy folder to obb location. Instead, open the game and let it get stuck or show error, then close the game. The folder of the package name of the game should be created
Now you can move the obb folder to the game folder
Enjoy playing!