Stormmetal Golem is a card you don’t want to be running. Whether it’s another Healing Mystic, another Dancing Blades or something else entirely, I’m sure you can, and should, find a replacement.
As you said, one ofs, unless they’re very specific utility cards, are probably not where you want to be. Regalia in particular is the kind of card where if you’re going to run it you want to have all 3, as it gets insane in multiples. Yes, I understand it’s Legendary and some people are on a tight budget.
Sundrop Elixir should be cut. It’s fine in the dedicated Lyonar heal deck, but that’s a different archetype from what you’re running. It’s centered around Zir’an, Lightchaser, Sunforge Lancer, etc. It’s probably powerful enough to get to Diamond but I think it’d hit a pretty hard brick wall upon getting there. It’s too combo-reliant and too dispel vulnerable to be consistently good at that level of play.
If you’re running Divine Bond, which I think should only be a 2 of at most, you ABSOLUTELY want Dioltas, as the Tombstone it makes is one of the best targets in the game for it. You already have 3 Ironcliffe Guardian, so that could give you a really strong foundation to build from.
I’d strongly consider adding the third Sun Bloom. Dispel is extremely powerful right now.
The last thing I want to say is that for a player clearly on a budget what you have right now really isn’t all that bad all things considered. I think you should be able to get to Gold and be relatively competitive there with what you’ve already got. I wish you the best!