How to replace string to node

Question

How could it be possible?
Here's my code. It doesnt work. How can I make something working like this?
https://code.sololearn.com/W0SfSMD4De9G/#html

Algorithm:
there is paragraph
there is word with red color
with RegExp one word in paragraph replaces to word with red color.

Answer 1

https://code.sololearn.com/WR8PWckD2H2y/?ref=app

Answer 2

@Yaroslav Pieskov thank you!