I have recently upgraded Magento 2.3.3 to 2.4.3 and installed claue 2 theme, and created my own child theme in separate folder (not user MGS folder), child theme works fine except that any layout override whether its core magento module or any 3rd party module is not working, for examples, I wanted to override wishilist display page, so I copied:
/vendor/magento/module-wishlist/view/frontend/layout/wishilist_index_index.xml
file to : /app/design/frontend/vendor/childtheme/Magento_Wishlist/layout
and made my changes there, and ran commands as: cache:clean cache:flush removed all static content and deployed again
this is happening with every module even if I try to override 3rd party layout file by creating that 3rd party folder in my child theme, its not reflecting.