For that, you have to override the course curriculum template and modify the accordion code. Please check our documents to know how to override Tutor LMS templates, the link is below.
That wouldn’t really work for me as I’d like to have the first accordion open for some courses but not for others. I’d also like to have all of them open by default for some other courses as well.
It would be preferable if you could instead add an “active as default” option to each topic in the course curriculum widget as is done in almost every other plugin that has an Elementor accordion widget.