Has it ever been established what chips are in these s19's. Is it not possible that these are still 7nm BM1397? Whatsminer is getting 86 th out of the 8nm?
I highly doubt that those are 5nm chips. Just look at the dimensions, it is much larger than the s17, so I believe they put larger amount of 7nm chips and run them on lower voltage (therefore the lower w/TH).