I found the Pleco app manages to do this task using the (free) option Screen Reader:
For example, browsing online in a website:
If we press on the button
, the app recognizes the characters and pressing on any character gives the pinyin and the translation:
You can even listen to the selected character or the whole text with the corresponding buttons: .
I wrote a simple tool to check whether your writing contains the allowed characters only:
I copied the allowed characters from the contest page you linked and added some common punctuation marks because otherwise they will be listed as not allowed. You can edit the allowed characters field however you like it.
That is the problem of TyperRacer, not the IME or you. I suggest you using platforms created by Chinese speaking people, which could be optimized for Chinese practice.
For example https://dazi.kukuw.com/keyboard.html
There is a website for Wubi lovers: http://www.52wubi.com/. Maybe it will be useful to you.
Some resources for learning and practicing Wubi:
Wubizi - gives full 汉字 examples for each of the 字根
清歌输入法 IME for Mac
WubiLearner form qinesoft
The reason that you can't find is simple: Wubi is not popular anymore. It was created specially for a group of elders, your grandparents generation whereas they are good in writing but very bad in standard pronunciation be it Pinyin or 注音 (Zhuyin) and too old to memorize Cangjie (仓颉). It totally disappeared when hand writing using touch screen came out. ...