No. The Doomicorn (Twitch Prime) and Demon Slayer (Amazon Prime) skins are server-side unlocks tied to your Bethesda account. No NSP update can bypass this; you must log in online.
Assembling the complete Doom Eternal experience on the Switch—Base NSP + Update v1.8 (UPD) + The Ancient Gods DLC—turns a compromised port into a truly impressive technical feat. The final patch solves almost all launch issues, and the DLC provides a hardcore challenge even for veteran Slayers. doom eternal switch nsp update dlc upd