Hi,
The multisite options are only available on multisite installations, it is disabled for convenience reasons. The primary keyword logic is visually disabled automatically, when you enable the exact matches function.
The word ‘2’ is not considired as a separate word when separate keyword matching by default, because the default option to consider a keyword is set to length of 2. You can change that here: https://i.imgur.com/SMYzXKq.png
Lowering that to 1 or 0 will force even single character words to be considered as separate keywords.
