Question Extraire des données entre des marqueurs à partir de plusieurs fichiers

#Combinaison des exemples d'origine
$Texte=@'
[1[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD]P]]
[1[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD][AAADDD][AAADDD]P]]
[1[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD]P]]
[AAADDD]P]]                                                                                                                 [1[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD][AAADDD][AAADDD]P]]
'@
 

#Texte de test
$Texte=@'
[1 UN [XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD]P]]
[1 DEUX [XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD][AAADDD][AAADDD]P]]
[1 TROIS [XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD]P]]
[AAADDD]P]]                                                                                                                 [1 QUATRE [XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[XXXXXX][AAADDD]
[AAADDD][AAADDD][AAADDD]P]]
'@
 
#https://docs.microsoft.com/fr-fr/dotnet/standard/base-types/regular-expression-options
#$regex=[Regex]::new('(?<=\[1).*?(?=P]])','SingleLine')

$DebutDeReconnaissance='\[1'
$FinDeReconnaissance='P]]'

#${ }  --> limite précisément le nom de variable Powershell.
$regex="(?s)(?<=${DebutDeReconnaissance}).*?(?=${FinDeReconnaissance})"
#$Regex='(?s)(?<=\[1).*?(?=P]])'

#Notes:
#
#Option de regex :  singleline
#(?s)

#Capture tous les caractères entre les deux textes de reconnaissance, et on capture le moins de caractère possible.
#.*?

#Assertions de préanalyse ( ce qui précède le texte recherché)
#https://docs.microsoft.com/fr-fr/dotnet/standard/base-types/backtracking-in-regular-expressions#lookahead-assertions
#(?<= )

#Assertions de postanalyse ( ce qui suit le texte recherché)
#(?= )'


Select-String $regex -input $Texte -AllMatches |
    ForEach-Object {$_.matches}
 

$Result=Select-String $regex -input $Texte -AllMatches |
            ForEach-Object {$_.matches.Value}

$Result.Count
#4