Hi,
I'm Sumit, here to answer your query at the Microsoft Community.
Apologies for any inconvenience you are experiencing. I am happy to help you today.
Although I am not an Edge developer, I find the idea of showing a duplicate tab in a split screen approrpiate. This feature allows you to work on a page while the original tab remains unchanged, similar to how the duplicate tab function works.
If you want to swap the left and right screens, click 3 dots on either tabs and select the Swap button. I added a screenshot for you.
Hope that helps, and rely on us for any further inquiries. All the best.