score:2
The website for the Saga Lounge has a list of all valid access options.
This list includes a number of Visa and Mastercard cards, but does not include either Priority Pass or any American Express cards.
Upvote:0
No for Priority Pass. See https://www.prioritypass.com/
Seems also a no for AMEX: https://www.americanexpress.com/idc/en/benefits/the-platinum-card/global-lounge-collection.html but this may depend on the details of your specific card.