Need help with mobile version

Hello everyone I need some help with my project.
When I go through articles on my computer there is a menu on the right side of the page that shows where you are now and it helps the reader to navigate through the content, but when you open the site on your phone there is no such thing. I understand that it’s all because of the size of the screen. Anyway, maybe there is an option to add it somewhere? Maybe at the very top of the page?

Or maybe there is any other way to organize navigation on the mobile version of the site, please share an idea.

My site:

That’s definitely one option. On scroll down, you could have a banner (that says Comparison Table) sticked at the top which gives you the drop-down list when clicked.

What I’d personally do is have it show up once you’ve scrolled past the title of the article (here, Top 9 Aquarium Thermometers Review 2020). And perhaps hide it when you’ve scrolled up past that point as well?

Another option is to have it stick at the bottom (like a mobile app menu). Easier to click as well. Perhaps try both to see which catches the eye more?

Nice WordPress theme by the way, whoever made it.