Your tank looks good and you have no problems. Chasing numbers means to create problems and most likely, if you continue like you suggested, you will have a lot of problems soon, like hair algae and cyanobacterial growth, slow growing or dying corals and maybe more.
If it is really phosphate and not phosphorus 90 µg/l (ppb) is all but sky high, it is only 0.09 ppm which in my eyes is in the optimum range.
Nitrate is most likely so low because you have growing corals and a good tank biology. This keeps nitrogen in flow and in the forms of ammonium, amino acids and other organic nitrogen compounds. Chasing numbers with nitrate may also create problems.
If my phosphate was only 0.09 I wouldn’t be chasing it at all. I use the Hanna ulr and 90 is 0.3 phosphates, not sure where you got 0.09 from but I wish my phosphates were there.
Why would lowering my phosphate from 0.3 to below 0.1 be a bad thing and cause all those things you just mentioned? Doesn’t make much sense to me. I thought the imbalance between phosphate and nitrates would be bad. Considering my nitrate is under 0.5 using Red Sea test kit and phosphate is 0.3