Combine the frame lock with a chain or U-lock with an ART 2-star (or higher) rating, which many Dutch insurers require for e-bikes. Always lock the frame to something fixed.
Amsterdam has dozens of guarded and municipal bike parkings, many free for the first 24 hours. Near stations and nightlife, they're far safer than a street rack.
Write down the frame number, keep your receipt and take photos. Without the frame number the police can't return a recovered bike to you.
A built-in or hidden GPS tracker greatly improves the chance of getting your bike back. Several models below include tracking and a recovery service.
A removable battery or display is a target on its own. Take them with you when you park for longer, and never leave the charger key in the lock.
First check whether the city towed it (Fietsdepot Amsterdam). If not, report the theft at politie.nl. Buying second-hand? Check the frame number at stopheling.nl.