A rewrite doesn't need to actually change the public API or experience using the software.

But by rewriting software, even in the same language we can learn from past mistakes and experiences and create better and more maintainable software.

Sorry, I think the idea that rewrites are good way to achieve more maintenable software is basically always based on a delusion. It is a very common and well understood delusion for programmers who always see the existing code as crap and imagine a beautiful world when they could only rewrite it. A well understood mistake: https://www.joelonsoftware.com/2000/04/06/things-you-should-...

In the context of free software it is usually also a method to be able to sideline part of the existing user or developer community, which you can not easily justify when making changes the existing project but can be achieved with a rewrite. But the former leads to a honest view of the trade-offs and consequences where the rewrite is a toxic power move.