D&D 5E Help me help my teammates make their saving throws.

I got started playing a level 11 campaign, and one of our characters is a Fighter(2)/Cleric(9) with 24 AC who walks around with spirit guardians on and destroys everything. It's great. Only problem is, in the first round of our boss encounter, he failed a dex save against a Beholder's petrifying ray (twice) and was out of the action for the remaining 2.5 hours of the night. (he happened to be the only player with access to greater restoration) I felt kind of bad for him, since I was playing a maximum Charisma Paladin with aura of protection and it still wasn't enough, so now I want to go all out, and stack every bonus to saving throws I possibly can in order to make sure my cleric ally and the rest of my party don't ever get petrified or possessed.

Here's what I've come up with so far:

Half-elf Bard(5)/Paladin(6) (College of lore, Oath of the ancients)

This gives me Bless, Aura of protection, plus 1d8 Bardic Inspiration, all of which can stack for a total of 5+1d8+1d4 (+12 on average) to a saving throw.

Aura of Protection is permanent, Bardic Inspiration is 5/short rest, and Bless lasts 1 minute but only takes a level 1 spell slot.

One more level in Bard gets me Magical Secrets, one more in Paladin gets me Aura of Warding. After that, I'll probably dip Hexbalde.

However, without Hexblade I'm extremely stat starved, needing +5 Cha and a stat to attack with, and I also need to be within 10 feet of the front line in order for aura of protection to function, which means I need good HP and AC.

Could a build like this be viable? Is there another way to support your allies' saving throws?

the lucky feat, 2 level dip in wizard (diviner) (doesn't work if you are set on front-lining as a paladin to give the aura) would give you 2 dice where you know the result beforehand (good rolls for saves, bad rolls to force bbeg to fail/use legendary action) and 3 dice for advantage/super advantage depending on the situation and dm ruling.

Play a Halfling with the Bountiful Luck racial feat from XGtE. Just to get rid of the worst result.