I don't resizing the image, jpeg 100% quality. Event tiff etc... I tried all the different setups.
By 1:1 you mean, doing the adjustment with the 1:1 view in lightroom, export it and compare the jpg in the 1:1 view too ?
I tried but they are not the same. It's really like the detail adjustments are not applied in the export. I don't remember have this issue before. I tried with 2 different mac (catalina and High sierra) last version of lightroom and camera raw on both.