Kindly check the grammaticality of the following sentence
For years, He wakes up at  5 a.m - Intended meaning- He is in the habit of waking up at 5 a.m, for years
Thanks in advance

Normally, we would say: "For years, he has woken up at 5 a.m." or "For years, he has been waking up at 5 a.m.", and "He has been in the habit of waking up at 5 a.m. for years".

But in a present-tense narrative we could conceivably say something like:
"For years, he wakes up at 5 a.m. Then suddenly his life changes and..."
But that use would be unusual.

"Used to" highlights a sense of contrast. Both are fine, and the simple past would be the default.

Note: "the Second World War" vs. (no "the") "World War II".