Transit time in Schengen country (Amsterdam)

If you are an EU citizen or a national of an EEA country or Switzerland, you can visit Amsterdam for up to three months at a time without any formalities. This more than covers any stay that could reasonably be described as "transit."

With a short-stay or long-stay visa (type C or D), or if you qualify for visa-free entry, you can spend as much time in Amsterdam as you are allowed under the 90/180 rule. For example, if you haven't been present in the Schengen area in the previous 90 days, you can spend up to 90 days there. This should also be more than enough time for transit unless you have exhausted your allowed days. If you don't have enough days, you would have to remain in the international area of the airport.

If you have an airport transit visa (type A), you can spend as much time as you want in the international area of the airport, but you cannot pass through passport control.

You don't specify if you are asking about the minimum transfer time, or the maximum transfer time. So assuming you are asking about minimum transfer time...

IIRC, the non-Schengen area at Schiphol Airport has a passport check separating it from the rest of the airport. If you are transiting from from one gate to another within the Schengen area, and any checked luggage has been checked through to your onward flight, the transit time can be quite short. If, on the other hand, your baggage is not checked through, you will have to exit through arrivals to retrieve your baggage and then re-enter through the security check again. That can take quite a bit more time.

KLM seems to agree on allowing more time for extra checks when they are needed: https://www.klm.com/travel/gb_en/prepare_for_travel/at_the_airport/connections/index.htm

Seems there's been some changes to improve the security processes at Schiphol since I lived in Amsterdam: https://insideflyer.nl/schiphol-central-security/