As with any huge deck that can afford it:
Put 6 six of these in. You have no excuse.
Anyway, your deck is quite cluttered, with some cards not helping your purpose.
Remove all cards that have only the sole purpose of attacking: Bone dragon, Flesh spider, Poison, Mummy, Sapphire charger, Hematite golem, forest scorpion, chrysaora, toadfish, firefly queen and physalia. Keep in discord, morning glory and Arsenic as alternative win conditions - a just in case scenario.
I'd recommend taking luciferin out too, replacing it with heal/miracle. Virus is quite meek, as well.
These cards slow down your deck quite a bit, which is a huge problem because you're playing a large deck. It would be better for you to play an outright stall, trying to deck out your opponent.
Then, once you've finished all of that, just fill your deck with cards that sort out your weaknesses - struggle to permanent destruction? Add in enchant artifact or cloak. Struggle to neurotoxin? Add in purify. I'd add in a good toolbox of removal to deal with most situations and threats. Sanctuaries, deflags, and lightnings are a good start.
I'll let everyone else fill in the gaps, as I'm not good with specific stalls.
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As a caveat, slower decks tend to make bad decks to use against the AI, as faster decks with similar winrate (and it's not hard to get a deck with good winrate against level4/bronze arena, even unupped) will simply give you more money over the same period of time. You can check for some decks
here.TL;DR: Make the deck a full-on stall, then build an actual arena grinder rush.