dnd 5e – How to improve passive character builds?

How can characters which have powerful passive/static abilities be improved to be more fun and dynamic during game play?

In this case, I have an 8th-level 5e Forge Cleric. AC 24, Fire/Poison/Cold resistance, DC 17 spell save; WIS 18, Warcaster. These are good attributes, to be sure, but in many gaming sessions, there is not a ton the character can do that is both helpful to the group and fun/creative for the player. The most useful actions are to keep Aura of Vitality or Spirit Guardians up, tossing in Healing Word or a bit of other damage here and there. Turn Undead is of course powerful, and this character revels in its invocation, but it’s not always applicable.

Once in awhile, spells like Heat Metal, Command and Water Walk are valuable, but these are situational, and of course require some foresight to have memorized. This is an 6-8 player group, where other characters have flying abilities, barbarian rages, invisibility, Misty Step, polymorph and other interesting ways to interact with the scenario. Others have super-useful spells such as illusions and Mage Hand.

What are some options to make this type of powerful cleric (or similar class) more dynamic and fun to play vs. more-or-less the same spell options in every situation?