If I understand correctly, you’ve set the Posts page to a page you’ve created? If so, this is no longer considered an Archive but a Page, which means your Archive template will not apply because the conditions are not met.
I’ll also add that WordPress looks for home.php and index.php when trying to access the Blog Post index.
Ah, ok, I was assuming that Cwicly would use an archive template that’s assigned as “all” for the blog/posts archive “design” - sorry, thats a hangover from Elementor where assigning an archive template to “all” includes the blog/posts archive too
So I suppose I would need to have 2x template designs that are the same - one for index (posts) and another for the other CPT archives - though I guess I could use a Cwicly “Template Part” for the design and call that from the 2 diff templates right?