Random idea, maybe make faith a currency again but have it work like diplomacy and loyalty? Spend faith to convert other cities, towns, IPs or reinforce your own settlements? It's the unit spam that makes this so tedious to me.
Some options like:
Create faith holiday in your Civ: Reinforce your settlements and add +faith per turn
Denounce other religion: Hinder faith generation for another Civ, add your faith pressure to their settlements. Worsen relationship.
Pilgrimage: Add faith boost for your Civ every celebration (generation per turn and pressure defense)
Holy War: Similar to Civ 6, allows you to start a war with another Civ giving you war favor and adding faith/happiness for each settlement you conquer
Government/Civic options can add a faith bonus, some allowing freedom of religion adding more happiness at the cost of lower faith defense, or only allowing your faith at the cost of some happiness.
Maybe add some balancing with tech where certain tech buildings may hurt faith generation? I think this would separate culture-focused Civs from tech-focused
Basically get rid of the units all together and make it an extra diplomacy or even Civic/Tech system. I will say it's a positive step away from how Civ 6 handled it, especially tourism (thank god we don't have to hear the multiple rock bands playing every damn turn lol)
Not a rock-solid idea, just a concept I thought would make it more interesting
