TiddlyWIki is the one place it is not stuck, I can't guarantee that for all the other places.
Why can I say this?
- The data is easily exported in a number of standard ways
- You totally control not only the data but the ways to manipulate it and export it.
- You have an active community that can support your needs
- You can save, duplicate and store how and when you desire.
- Of course advanced features like macros are not so easily transferred, but then they are bonus features.
However I think what you are actually asking is what Jed refers to and that is formatting.
- If you have a systematic and often repeating need to do so you can build or use a process to convert to and from WikiText.
- However if it is a one off transfer, obtain the details of the different markups involved (eg; Bullet list, headings) for WikiText and WikiMedia and use a good editor such as NotePad++ to systematically find and replace one markup for another.
- If you do go down this path I can give additional advice, such as use intermediate values eg convert \n! and \n!! to \n<hd1> \n<hd2> (where \n means new line) such that you can later change these to the destination format. Without hitting other examples of "!"
- If you keep notes of the steps you took to achieve this and it can be generalised we can use this info to build a process in tiddlywiki or elsewhere.
- There will be case where a leading "!" means heading in wiki text, but in another the == heading == needs to be wrapped in for example ==, this may need other tricks to handle conversion, or manual intervention to add == to the end of each line beginning ==
- Once again its all about how much and how often as to which approach to follow.
There are I believe also existing solutions to translate WikiText into other markup/markdown language which you may use to convert WikiText into an intermediate format, the use an online conversion tool to change into MediaWiki wiki text. PanDoc
https://pandoc.org/MANUAL.htmlFor example Print as PDF and Convert to WikiMedia, or Print as PDF use open/save in word then convert word to WikiMedia.