Bless at low-to-mid levels and spirit guardians later are the best things Shadowheart can spend her concentration on for, like, 95% of situations. Both spells are extremely good, just like they are in the tabletop. Never understood people criticizing Shadowheart for being useless; she’s a Cleric, and that’s great already even if her subclass (which you can respec her out of) is subpar for the class.