ANSWER:
No problem in praying one rakah of witr everyday.
Of course there’s a difference. The more you pray the more reward you would gain.
The most authentic opinion is that qunoot should be recited after you rise up from ruku.
Reciting qunoot in witr is not mandatory. Your Witr is still valid even if you don’t recite qunoot.
Witr is not obligatory, it’s a highly recommended sunnah which the Prophet salla Allahu alaihi wa sallam never used to miss even while he was traveling.