You download Tiddloid from its github site:
Same for Quinoid
AFAIK, the extensions that used to work in browsers no longer work on Android. But you can use the download saver mechanism. Unfortunately, on Chrome at least, it not only changes the suffix of the file, it also changes the prefix. However, if you only want to VIEW a TW file, then any modern browser will work.
Another possibility is to run node or tiddly server on your device inside of termux or some other application that supports node.