No, NWC wallets take many forms. If you’re already running a node you can use Alby Hub, but you can also get a NWC string from a lot of other wallets. Just be aware that custodial wallets are not intended for long-term storage and you should not hold too much in them.
Here are a few ways you can spin up a NWC wallet to plug into Primal and other apps.
nostr:npub1yzvxlwp7wawed5vgefwfmugvumtp8c8t0etk3g8sky4n0ndvyxesnxrf8q (free, custodial)
nostr:npub1jluy3twvf338v6zlujzzdhjkzjy8ezj34ksydr8vw8a6jwp89ygshpp2kq (free, custodial)
nostr:npub1ve8qwrlztemdmnh62jffcr0y9m9dpqgqjdg8ufx7gc3qw5wdk74qyv9ka6 (paid, custodial)
nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm (paid or free, non-custodial)