@Sylvain-Jean, is this a Notepad++ question or a regular expression question? This forum’s focus is supporting the Notepad++ editor, and at times people have questions about Notepad++'s search/replace feature.
If you are using using Notepad++ then you may be interested in the Generic Regex: Replacing in a specific zone of text article.
However, I personally don’t think what you want can be done in a single search replace as you want to do several things.
You want search/replace the string <property name="ServerLoginConfirmationText" value=" with nothing.
You want to keep the string For in game information, be please to ask question to ingame admin
You want to replace the comma-space that is after admin at the end of the previous string with a comma-newline.
You then want to replace the spaces that follow comma or semicolon with a newline up until the " />
You want to replace the " /> with nothing.
Before proceeding further, I suspect you should think more carefully about what you are asking for. That’s because while it can be done in two steps they are are rather specific to the example data you had provided:
Search: (?-i)(?:<property name="ServerLoginConfirmationText" value="|" />)
Replace: (nothing)
The string is now: For in game information, be please to ask question to ingame admin, those are; XXXXX, YYYY, ZZZZZ and so we then deal with that using:
Search: (?-is)(?-i:For in game information, be please to ask question to ingame admin|(?!\A)\G).*?\K(?-i:(?<=[,;])\x20)
Replace: \r\n
The latter expression is straight from the article I linked to above using (?-s)(?-i:BSR|(?!\A)\G).*?\K(?-i:FR) where
BSR is For in game information, be please to ask question to ingame admin
FR is (?<=[,;])\x20
The BSR is longer than you’d think as you wanted to preserve the comma-space in that string.