Opinion on next med to add

I first started showing significant symptoms of MCAS in November 2022 and was diagnosed as the disease worsened in July 2023. My main symptoms were/are daily tachycardia (laying 110-120, sitting 150s, standing 160-190), near syncope, dystonia, and food intolerance bordering on anaphylaxis. I was able to stabilize with xyzal 10 mg twice a day and ketotifen 0.5 mg twice a day. I stabilized to a point that I was looking to decrease my medications and otherwise live a normal life eating anything/using products etc. I recently got COVID and have had a flare up comparable to when I first started having problems with the disease including extreme tachycardia, sob, and food/physical/environmental intolerance (to the point where i was having reactions to water which included my HR shooting up to and sustaining at 150 bpm with a single sip). I have increased my meds to xyzal 10 mg twice a day and ketotifen 1 mg three times a day. I am thinking about either adding zafirlukast 20 mg BID or quercetin. I am avoiding montelukast because of the black box warning. However, because my main lab work to be out of range is my leukotrienes, I feel that this might be a good next step. I would ideally like to avoid adding another medication if I can help it but I definitely need more stabilization, which is why I’m considering the quercetin. Please let me know your opinions and experiences with quercetin and/or zafirlukast including (if you feel comfortable) what your symptoms were, what meds you were on, how long it took for the medication to kick in, and if you had good results/any side effects? Thank you in advance!!