Any suggestions on what’s happening with this pl...

Oh sorry, didn't see you already did half of that (the calmag and semi-flush)... Still, I'd recommend some epsom salts/sulphur and even a bit more calcium(especially if you use more epsom salts) along with a general feed (even like molasses and kelp, something that has varied elements but at fairly safe levels). And just maybe, a bit of citrus juice or citric acid (as it can chelate and improve nutrient uptake).

Looks like you got SERIOUS toxicity issues there. Lay off whatever nutes (unless they are VERY mild and quite general, like not just NPK shit, some microelements, etc). And then, I'd recommend a little calcium, epsom salts (mainly for the sulphur, but so that it kinda goes with the calcium) and potentially a tiny bit of boron. But this is very speculative, just trying to mention sort of mostly safe, potentially buffering things. You'd have a better idea of the pH and shit.

She is looking hella stressed. i think with all the issues you have been having she is reacting to the treatments she has been having. Just give her some tlc for the nxt couple of weeks and she will bounce back. Good luck and happy growing