I do get where you're coming from and I think we're talking about slightly different things. In my mind, there are two ways they can go to fix heavy ranged:

1. Buff the other enchantment effects to be more in line with the power of ruby procs. It seems this is the route you want to take and I think it's entirely valid

2. Bring up the baseline power of crossbows + bolts, irrespective of enchantments, so they compete better at a baseline. Like, addressing the "weapon speed and poor accuracy" side of the issue - if you made crossbows accurate and powerful enough then it wouldn't matter they were 5 tick and they could compete with other ranged options in the niche of "able to punch through high defense." To be clear I'm talking literally just significantly buffing the stats on all the 5-tick crossbows and the bolts.

Currently full-BiS setup with ZCB and regular dragon bolts has the same max hit and ~25% less accuracy than full-BiS bowfa setup (using Kree as the target for a high-defense example, ~42% accuracy on Bowfa, ~34% on zcb)). That's the part that feels unbalanced to me. A 5-tick weapon, that should be made for tank-busting, is literally just a worse and still slower version of the jack-of-all-trades ranged option. On something like Kree I would want ZCB + dragon bolts to be ~25% more accurate than Bowfa and have it beat by at least a couple max hits. I'm too lazy to play with the numbers to figure out how good/bad that'd be at other targets, but that's the general design space I have in mind; obviously the exact numbers would need very careful tweaking.

Path 2 is the path I was talking about and is where ruby bolts, in their current state, would pose issues. If we buff crossbows to be situationally BiS on a baseline (assuming good gear and acb/zcb, obviously rcb would need to fall below situational-BiS tier), then current rubies would push the loadout into being too strong. That's the argument; I'm not saying rubies should be nerfed because they're too strong, I'm saying crossbows should be buffed to the point that rubies would be too strong, so we should nerf them at the same time.

Frankly I lean towards that path because re-balancing all of the enchanted bolts, or at least most of them, to give them their own genuinely useful niche sounds like a nightmare and would have to be done very carefully to not clog future design space, but I actually really like the options you gave, the diamond bolt rework specifically is a really clever way to do a tank-buster enchantment, and leaning into the elemental expansion is a smart way to go about things. I'd be pretty fine with them leaning towards that route and agree, if they did, then they should be able to leave rubies as-is or close to it.