I believe most here are in agreement that a run is more like 70-80mins also idk why you would be doing RvB every day or how that would take you 20mins (at most 10mins once every 3 days)
using your formula though lets do it this way
75*x=2.5m*0.625 which 75*x=1562500 where x now = 20.8k per alex (or pretty much what its at now) to be equal to time vs profit on your server
on my server its actually a bit less with currency prices in the decline (lost 1k in the last 3 weeks alone on some of them) where the average price is closer to 6.7k per piece with hundreds of forgottens left sitting putting those in decline (hopes alone have lost 15k in value in the last month)
for my server its
75*x=1490.625 where alexandrite only has to be 19,875 gil each add in the convinience of 3 boxing only to enter vs having to do it all the way through and its quite compairable or even more profitable than dynamis time and effort wise at current prices (and while alex currently maintains its level of value with ancient money dropping it will only be more profitable)
also this does not even take into account boss pouch so thats probably able to be even cheaper and still be equal to dynamis profits
edit: math with boss pouch 95 average assumed at a 25% drop rate with 80 (I like even numbers) average coins
95*x=1490.625 where each alex to equal to todays dynamis profits only needs to be actually 15,691 gil (so actual values probably about 16k each)