

apparently then it was around 20% to 25% as well
No, the unemployment rate was around 20-25% under the traditional definition. It’s currently 4.2% under that definition.
If you want to use this LISEP definition, fine, but recognize that it’s been above 30% for most of its existence, and has only been under 25% since COVID. Basically, if you go by the LISEP definition then you’re saying that the job market after COVID has been better than it has ever been before.
No, LCOE is an aggregated sum of all the cash flows, with the proper discount rates applied based on when that cash flow happens, complete with the cost of borrowing (that is, interest) and the changes in prices (that is, inflation). The rates charged to the ratepayers (approved by state PUCs) are going to go up over time, with inflation, but the effect of that on the overall economics will also be blunted by the time value of money and the interest paid on the up-front costs in the meantime.
When you have to pay up front for the construction of a power plant, you have to pay interest on those borrowed funds for the entire life cycle, so that steadily increasing prices over time is part of the overall cost modeling.