Which is the best and easiest way to learn the Bhagwad Geeta? And other Epics, Vedas and scriptures etc, in both audiovisual forms etc.
It's a good question. Please note: that Gitas, Upanishad, and Tantra are Rahasya Literature (Secret Literature) that was only given to eligible students by realized Gurus. So they are not meant for casual reading. They are not meant to be translated word to word. If one reads a word-to-word translation two things will happen. 1st they will lose the entire context. 2nd they will treat them as Religious commandments and become a cult. As the other member's answer says: "Please don't read cult or sectarian version". General masses were always given Aagamic Practices, Itihasas, and later Puranas through Pravachana (detailed explanation given by scholars on open platforms during various religious events to understand the concept called Tatva).
Coming to Vedas (the Samhitas, Brahmanas and Aranyakas). Please note the Upanishads we already covered above. "Vedas" is not a single book or a volume of books. There are 4 Vedas and each Veda has many branches called Shakas. At one time there were over 1180 Shakas. Today only 14 Shakas survive and not all are in practice. So, if you want to read them, that means you can only read the translated version of the Manuscripts that are kept in the Universities. Many researchers of Sanskrit tried to translate it and find its meaning. The issue is, each of them came up with their own version. Some are close and some are far apart. So, no matter what you read or which translation you read, you will end up with an OPINION and not knowledge. The only widely recognized Bhashya of Vedas by a native Scholar was Sayana. Many other western scholars like HH Wilson relied on Sayana as a basis for his comparative analysis. You and find his work on Internet Archieves.
What to read? Whom to read? One who has an inquisitive mind and wishes to explore has to use a Bhashya (commentary) given by Prodigies, and realized beings. The first collection of Bhashya across Upanishads + Sutras + Tantra + Bhakti + Gita was given by Child Prodigy Adi Shankaracharya over 1500 years ago. 600 to 700 years later many other Acharyas tried to give similar Bhashya influenced by Puranic literature.
Where to read? For Gita: IIT Kankup University has created an amazing portal for Gita with side by side collection of many translations. Here is the link Here is a list of all Bhashyas by Adi Shankara. You are welcome to choose other Bhashyas. Here is the link