Who should own my trademark?

The proprietor you choose affects who can sue, who can sell and what happens if the business changes. Pick the closest situation.

Moderate complexity - several routes or missing facts

Apply in the name of the legal entity that will use and own the mark. If a founder files personally and the company uses the mark, document the arrangement.
A registered mark can be assigned with or without goodwill, for all or some of the registered goods or services (section 38). The new owner applies on Form TM-P with a certified copy of the document and a statement of case (rules 75-76).
If you are registered as a startup under Startup India or qualify as a small enterprise, the Rules define those terms (rule 2).

The honest answer usually needs someone to look at your actual disclosure, your timeline and the prior art. That is a conversation, not an article.