How to use Regular Expressions correctly in the Rule Engine Node

I would like to filter numbers or words with the Rule Engine Node. Everything works fine as soon as I don’t use regular expressions. Then the Rule Engine Node no longer filters out.

But it can’t be because of the regular expressions, as they generate unique hits in https://www.regextester.com/ and do exactly what they are supposed to do, such as

(.)\1{9}

→ returns all identical characters from 9 repetitions onwards

(0){9}

→ returns all 0 from 9 repetitions onwards

^[0]*$

→ returns everything that has 0 throughout

OR

\bFOO → returns all words that are FOO

(FOO) → returns all words that contain FOO

I also think that I am using the correct syntax:

$column-Name$ MATCHES

 "^[0]*$"

=> 1

$column-Name$ MATCHES “(FOO)” => 1 // if true, then prints a 1

But at the end there is a 0 in the column to be appended. Everything I map with the syntax $column_name$ = “FOO” => 1 works perfectly. Only the regular expressions do not work. But I need them, because there are often other words after FOO.

What is going wrong here? Why are my regular expressions not working in the Rule Engine Node?