Complete electrical loss

Follow the smaller battery positive wire to the under-hood fuse box. Clean and tighten that connection. That is a common cause of this problem on almost all car brands.

Also follow the smaller negative battery wire to where it bolts to the body sheet metal. Be sure that connection is tight and not rusted. The strands of that wire can also corrode back under the insulation where it can't be seen.

This complaint used to be caused by loose or dirty battery cable connections, so check those too. Here's a link to a related article:

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

Please let us know what you find. We are interested to see what it is.