Forgot to add the values

custom_components/tuya_local/devices/YX-025WB_aroma_diffuser.yaml

@@ -21,8 +21,11 @@ primary_entity:
       name: preset_mode
       mapping:
         - dps_val: small
+          value: small
         - dps_val: large
+          value: large
         - dps_val: interval
+          value: interval
 secondary_entities:
   - entity: light
     icon: "mdi:light-recessed"