Maximum Number of Indexers

Random question. I have a number of indexers setup (6-7) in an attempt to case the widest net for less popular shows. But every time I search, Sonarr only says it’s using 4 of them. Am I missing something? Is there a maximum number of indexers that Sonarr can work with at one time?

No maximum.

Do they all support that series type (not all indexers support anime and anime only indexers don’t support standard/daily shows)?

Do they all support search and have search enabled?

Lots of reasons why they wouldn’t be used.