Login to LG Content Store and install OttPlayer or DuplexPlay (depending on your region). Once launched, the application will show the UID - take a photo or write it down.
Go to the application website from your computer, create an account and add a device by specifying the UID. Then download the M3U and XMLTV files, name them, and assign them to your device. After synchronization, the channels will appear on the TV.
If the app is not available in the store, switch the LG ThinQ region to Poland or Turkey (Settings → General → Location). After installation, change the country back. For stable playback, turn off power saving mode and update webOS to the latest version.