My assumption is that if they contain the Snarl long-term, there won't be a need for a "next world" and thus Hel's starvation* is unlikely to be an issue. If the world continues, she'll still get Belief and Dedications on top of her existing souls.

(Furthermore, she actually has a high priest of her own now, so she's definitely in a better spot than she was prior to the Godsmoot - even having lost both Greg and Gontor, she may now have a way to obtain some fresh Worship too, e.g. by founding a church. Loki, despite his distaste for undead, may even help with that as an apology.)

*We're also assuming she would starve. She's not looking too hot right now, but there's still only a chance she doesn't make it if the world gets unmade.