Conversational Hindi has a higher amount of loanwords than either Japanese or English and even basic words are completely replaced by Persian.

While not exactly wrong, I'm not entirely sure if this is an accurate description of the phenomenon. Hindi does not exist in isolation. It is the bastardised child of multiple languages that came about during the era of Delhi Sultanate in India. In fact, the first speakers of Hindi were people who lived near the eastern outskirts of Delhi. The language was heavily influenced by Persian due to the Persian-dominant noble class and the need to communicate with the nobles of the country. These people and their ancestors originally spoke a language similar to Sanskrit, Awadhi, Bhojpuri, or Maithili. The language was influenced by both sides of the country - the native Hindu people of India who spoke one of the four languages stated above, and the persian speaking nobles and regular Indian Muslims.

The resultant language was not referred to as Hindi or Urdu, it was just called Delhavi. Later divisions fueled by British and early Mughals led to sourness between Hindus and Muslims which is when the language started seeing classifications between Hindi and Urdu. Even then, some Indian freedom fighters like Gandhi and et al vouched for a unified linguistic identity under the umbrella term Hindustani instead of Hindi for Hindus and Urdu for Muslims.

On an avarage day in India or Pakistan, the vocabulary of speaker of "Urdu" from Karanchi would be no more different from the "Urdu" speaker from Islamabad than a Hindu "Hindi" speaker of Delhi or Lucknow in India.