[Switch] Sunless Skies: Sovereign Edition $15 @ Nintendo eShop

There's also the first game in the series, Sunless Sea: Zubmariner Edition $10.20.
All time low for Sunless Sea on the Switch was $7.50 back in Dec 2022, but the current price is still better than the Sunless Sea + Zubmariner bundle on Steam (currently $16.91).

If you want them on PC, you can find it for:

• Sunless Sea $9.16 - This is just for the base game, not including the Zubmariner DLC.
• Sunless Skies: Sovereign Edition $14.38.

Sunless Sea has a Metacritic score of 81% for critics, and 7.5/10 for user score. 83% positive on Steam across 7,039 user review.
Sunless Skies has a Metacritic score of 87% for critics, and 6.9/10 for user score. 84% positive on Steam across 2,329 user review.