I would like to know precisely how Trump's lies, specific to COVID-19, have cost lives. [...] I want to know who would do things differently, what they would do differently, and how that would have saved lives during this pandemic, if Trump had instead told the truth (and specifically what truth should he have told instead of his lie, and when should he have told it).
This is an unreasonable level of detail to demand, since to satisfy your requirements we would need to accurately predict the actions of every alternative president. And of course Trump has told many lies. I think you only have a right to expect broad analysis of his most egregious deceptions.
Because as I recall the whole country went into lock-down and across the country people were ordered to wear masks, with business given powers to throw you out and police given powers to ticket you if you did not wear masks.
Lockdown is not a binary concept. Many GOP state politicians live in fear of Trump's public disapproval, since GOP primary voters are very loyal to Trump - many GOP politicians who opposed Trump have lost their primaries. And also to a lesser extent because of public protests encouraged by Trump. As a result, many GOP states and probably to a smaller extent some democrat states implemented less severe lockdowns that they otherwise would have.
So Trump's beliefs sure didn't stop any of that!
It is an error to speak here of Trump's beliefs, since it's clear from e.g. statements to Woodward and his hygienic precautions he was aware the pandemic was dangerous. It was his statements, more precisely his lies, which caused the deaths.
There were and are many people who refused to comply. Trump did not order them to refuse. Are we saying that if Trump had changed his tune that these teeming masses of rebels would have all changed their tunes too? Because that seems unlikely to me, as these rebels are refusing to wear masks due to their own ignorance and pride, not due to the president's words.
Some would have. But Trump has enormous influence and respect within a large minority of the population. Certainly far more flouted the mask and social distancing rules because their president advised them the precautions were unnecessary. Certainly many adopted conspiracy theories that masks were harmful, because their president told them the virus was a hoax. Some would have anyway but in pandemics numbers matter.
I also understand that many states lifted lock-down too early. Were those state governments doing that because Trump lied?
Some of them, yes. For the reasons given above.
What good is a ticket to the good life, if you can't find the entrance?