Zardnaar
Legend
Using Protector mode on the Eldritch Cannon and all spells as Cure Wounds versus a Life Cleric using all Cure Wounds (including 2nd level) means with an average encounter day the Artificer provides more HP potentially while the floor of the Life Cleric is higher thanks to their bonuses.
Plus, the Eldritch Cannon's protector is merely a Bonus Action
Aware. Killing everything faster is also another way of preventing damage. Or stopping the attack all togather.
Also depends how often the cannon gets nuked. Eg via AoE. 5.5 critters have some brutal abilities and AoE. It cant sit at the back and spam temp hp.
Looks very good on paper though. Homonculi, wand of MM, temp hp lvl 6 for example. Drain the wand transmute it into a dazzling weapon hunt if to a PC. Combine with true strike repeating crossbow as your arcane firearm.
Its ticking a lot of boxes for level 2-6 play and 11+.