I have just tried with Xcode 26 RC and still get the same error "ITMS-90717: Invalid large app icon". I have tested with only SVG files, with only PNG, where one was w/o alpha, and with combination SVG and PNG. Nothing worked. I sent feedback with attached AppIcon.icon file.

Turn off Blur for the group fixed this issue and was able to submit app for review. It is not the best but at least is a workaround.