No, your 18-watt power adapter won't get you 15-watt fast charging with the MagSafe Charger : r/apple
Samsung Fast Charging EU Mains Travel Adapter 15W (1.5m USB A - USB C
Official Samsung 15W Super Fast Charging USB-C Plug and Cable Black – Fonehaus
Samsung Galaxy Official 15W Adaptive Fast Charger (without USB-C to C Data Cable), Black: Amazon.co.uk: Electronics & Photo
Williams Electrical | Hama 187264 Wireless Charger, 15 W, Turbo Fast Charge | Sheffield
1 AMP 15 VOLT 15 WATT AC/AC POWER ADAPTOR SUPPLY CHARGER TRANSFORMER -MULTI JACK | eBay
Buy Samsung 15 Watts Adapter, Single Port with USB (White) at Reliance Digital
Samsung USB Home Fast Charger 15W With USB-C Cable 1.5 m White| Techinn
Samsung fast charging adapter Duo EP-TA220N Black (max. 35 W USB Type-C, max. 15 W with USB-A, without cable
for iPhone 15 Original Adapter Pd 20W Power Supply USB Type C Fast Charger UK Plug 3 Leg Adopter Cargador - China Apple 20W Adapter and iPhone Fast Charger price | Made-in-China.com