Thanks for the advice. The past few posts have been good and have echoed a lot of what I've been going over in my head.
One of the things I keep asking myself is, "What does Ren do, and how can I make him better at that?". Right now his major contribution is just making sure the casters don't get hit. So far he hasn't needed to expend many spells on Healing because he is the one who has taken the hits. In fact I'm pretty sure the Sorceress and Warlock have barely been scratched this entire campaign...so far.
In terms of Action Economy, getting that 2nd Attack with 1 more level of Fighter is crucial to basically double my base damage since I predominately use the Attack action for base attacks. My Bonus Action is pretty much used up by using the Shield Mastery Shove in order to try to get Advantage on my attacks (unless there is only 1 enemy and the casters are slinging spells at it due to the Prone effects) and to limit the movement of the enemy. My Reaction is either utilizing the Protection feature or a Riposte, with the priority being towards Protection (which I am starting to see lose value as we encounter more and more enemies with multiple attacks).
Spellcasting-wise. I have not seen a huge benefit for keeping Bless going, so I have not cast it since Level 2. All the other players are sporting at least one ability score of 20, and all have their primary attack attribute with a 20 so there have been very little if any misses. Similarly, with my AC being 20, I very rarely get hit so I have never once used the Shield of Faith spell. I think I've used Guiding Bolt twice in the entire Campaign, and the Light Domain bonus Burning Hands once. I probably shield put Healing Word on my "memorized" list, but thusfar I have mostly used Cure Light Wounds to patch myself up after a fight when we have been unable to rest.
I suppose the best option is to simply go from my current Figher 4 / Cleric 1, and go Fighter - Cleric - Cleric - Cleric - Cleric to ge to Fighter 5 / Cleric 5. There is that extra ASI waiting at Fighter 6, but honestly I just don't feel I need the ability score improvement and I can't think of a game-changing Feat that doesn't conflict with what I already have. I definitely see the strategy of grabbing Resilient to get proficiency in a different save, but Lucky is basically giving me Optional-Advantage on all saves 3/day.