Regex match from start label until empty line or end label

Question

How can I match the content between a startlabel and either a empty line or an endlabel with a regex?

For example regex101 link:

<START> some text is here. 
more text

unrelated text

<START> even more text. 
text text
<STOP>

It should match two matches

<START> some text is here. 
more text

and

<START> even more text. 
text text
<STOP>

The regex I came up so far is as follows (but it matches the whole text, I assume because of the (?s).* part).

<START>((?s).*)(\s\s|<STOP>)

Answer 1

You should use a lazy quantifier for .* to match as few as it can. Using .*?:

(?s)(<START>.*?)(?:(?:\r*\n){2}|<STOP>)

Leaving out of the group what you specified as ending conditions.

1. (?:\r*\n){2} an empty line.
2. <STOP> the end label.

DEMO

Answer 2

You can design your pattern like this (with the modifier m):

<START>[^\n<]*(?:(?:<(?!STOP>)|\n(?!$))[^\n<]*)*(?:<STOP>|\n$|\z)

demo

The idea is to match all that is not a < or a newline with [^\n<]*. When a < or a newline is reached, negative lookaheads check if they are not followed by "STOP>" or an end of line. If the negative lookahead succeeds then [^\n<]* (in the non-capturing group this time) reaches the next < or newline. The group is repeated until <STOP>, two newlines, the end of the string.