if you  make a
from PySide6.QtWidgets import QTableView
or 
from PyQt6.QtWidgets import QTableView

table_view = QTableView()
and then do 
table_view.setLayoutDirection(Qt.LayoutDirection.RightToLeft)

or

table_view.setLayoutDirection(Qt.LeftToRight)
it causes several issues.
vertical headers become unselectable, 
self.table_view.selectRow(0)
and
self.table_view.selectColumn(0)
dont work anymore.
if you drag and drop a row it becomes the whole selection goes crazy. 
 

this is also true if you change layout direction on the app level. 

meaning this issue exists if you do 
Qapp = QApplication(sys.argv)
Qapp.setLayoutDirection(Qt.RightToLeft)
or 
Qapp.setLayoutDirection(Qt.LayoutDirection.RightToLeft)

also horizontal scrolling at least on a Mac with finger gesture is going the wrong direction

I have attached an example