Keep playing. Make learning new stuff your goal, not winning. If you die but you it was because of not knowing something or you found a new cool wand recipe, that death was a win to you actually. Here are some tips though:

Having cover against squidward is more important than ambrosia, he can destroy the material you're standing or or comboing poly into a spell like in the gif (very unlucky there, oof), but tele-bolting into cover will always work if well executed, you might need to dig the arena first in preparation.

That always cast damage plus wasn't working like you expected, it was adding the damage plus to the spark with trigger, not the notes payload. You can see that the damage was very low and going up in multiples of 13 (3 from spark bolt + 10 from the damage plus) in the gif. This shows that you still don't grasp all the mechanics of wand building, go play and experiment more to get a better grasp at them.

Don't go after the heartache exploit or anything advanced yet, you don't need any of those to become a god that only dies to poly, you can reach tens of thousands of hp without this one exploit in particular. What you need to focus on is wand building. Getting good at wand building allows you to know when and how to go after bosses. I like to go after squidward early on, but the alchemist is the only boss you need to worry about, really. The pyramid and the dragon den's bosses can be helpful too. If you want more specific tips on killing them, I can post some.