Payment processor choice

Hello. I own a street food caravan since 2014.

Taking payments has evolved a lot, our clients ask us to make card payment available.
We are unsure if we should go for Square-up, paypal or any other type.

The want to implement EMV especially Contactless. My questions are.

1) How many contactless payments can be taken before clients will be asked to introduce pin number. This is an issue as we want to keep a fast flow.

2) How to handle friendly fraud

3) Regarding both of the above, which…

Payment processor choice