I think DD should come from legal filings and audited financials (signed off by a reputable auditor)....like what an SEC reporting company would do.
Thats definitely a big part of it, I agree but its way more than just filings and financial statements. You need to dig further, find a source that can take pictures of conferences, the actual product (EV), research members of the company, have a conversation with members of the company, etc. Members here have nailed this one on the head.