How to safely change the theme in WordPress.

I want to change the theme on my site. How to make it as safe as possible for the SEO?

I would make a dev site and make everything work there fine, and after that just migrate that on live domain. The theme itself shouldn't be a big problem, except if there is a difference in builders, or let's say you were making your posts in Elementor and you are switching to Bakery Builder. It will break the look of those posts.