If you go to Toolset > Settings you can choose whether you want to use the legacy editor or block editor (or have both options available) and specify which editor should be used specifically for Content Templates and for custom WordPress Archives.
Your screenshot doesn't show the setting for WordPress Archives, did you change that, too?
It may be that you need to delete an existing archive if it was created with the block editor if you want to be able to make an archive with the classic editor for the same archive.