Ez Typo3 use categories in fluid and News Extension RSS

Hey, i have a view ez things to do.
1) The target: to use page categories uids in fluid template for things like conditions:
like
<f:if condition="{pageCategories.uid} = 10,12,15">
Will shown this part of template
</f:if>
i have already this typoscript to create these, but it dont works or im not smart anough to make it work ^^:
dataProcessing {
10 = TYPO3\CMS\Frontend\DataProcessing\DatabaseQueryProcessor
10 {
if.isTrue.field = categories
table = sys_category
pidInList = root,-1
selectFields = sys_category.*
where = sys_category_record_mm.uid_foreign = {field:uid} AND sys_category.parent = 1
leftjoin = sys_category_record_mm ON sys_category_record_mm.uid_local = sys_category.uid
where.insertData = 1
recursive = 1
as = pageCategories
}

2)
I want to use the news rss by georg ringer, in an multidomaininstallation for every Root an own.
i have no idea why it dont works what i copy and pasted from this website:
https://docs.typo3.org/p/georgringer/news/9.1/en-us/AdministratorManual/BestPractice/Rss/Index.html?highlight=rss