Шаблонная обработка сфинкса

Документация https://www.sphinx-doc.org/en/master/templating.html#working-with-the-builtin-templates говорит, что искомый шаблон - layout.html .

Возможно, вам стоит использовать это имя.

This works for me. Perhaps you need to force a rebuild for all files with the command sphinx-build -a? Sphinx only compiles HTML files that it detects as having changed. Another option is to just touch all your source files with touch *.rst.