I wrote the RegEx feature to be case-insensitive by default, as it uses the =>gmi flag.
Add =>gm at the end and it will be case sensitive.


For example,

#RegEx=>a=>b will be case insensitive and replace all letters a with b
#RegEx=>a=>b=>gm will be case sensitive and use the global and multiline flags.

Note
You can use \b word boundaries, so it only replaced whole words.
A great place to experiment with RegEx to see what it does is RegEx101 website.