Even with LTSC you can't disable all telemetry, It could have been a great (and very popular) option for companies (even though it wouldn't help home users), but MS didn't want that and discouraged its use in everything but the most extreme cases (https://www.computerworld.com/article/3326065/microsoft-tras...) even before they cut support to 5 years instead of 10.

Maybe things will be better with windows 11?