How does switching from WordPress to custom-made Python site affect SEO?

I want to switch from WordPress to a site I want to build with Python and the JustPy web framework(Python wrapper built around Quasar).

I plan to use things like Steppers and other tabbed features that do not immediately show the content when the page loads.

My question (fear) does that tabbed content affect SEO in some way?

Also, I know Python well, but I have no knowledge of how to optimize HTML for SEO. Are there other negative outcomes of switching from WordPress to a custom-made Python site SEO-wise?