Some feedback would be nice, what can I do to improve it and also if it's gonna yield anything decent or it's gonna be small airy crap

All RO water is going to be adjusted for growing cannabis! Period! Done! Happy gardening

Think the clawing is climate-related. Temps and rh not jiving... Mottling and thin leaves up top.. Some interveinal chlorosis... When it's a smorgasborg of symptoms, it's nearly impossibly to diagnose only from visible symptoms. scraggily new growth.. number of fingers not increasing etc.. the overall formual is out of balance even if you fix the more predominant symptoms. marijuana brands try to reinvent the wheel. I'd suggest sticking to a ratio and concentration you see for Jacks, masterblend, southern ag, cropsalts, megacrop, kosher-something brand etc... they all adhere to an existing knowledge base that's far more comprehensive than anecdotal stuff that is the basis of pop-up marijuana brands that never hired any chemists or referenced existing knoweldge before selling mostly junk. there are apps that will calculate dosage to hit these targets based on your guaranteed label info.. the brand is irrelevant when it comes to soilless/hydro cntext. 100% plant available and 100% soluble is a pretty low bar to meet. Better brands have a well-buffered pH too to make life easier. The ratio and concentration is the key. Good formulas work on 90-95% of all marijuana plants. Shitty formulas are why there's a false perception that these plants are picky eater. It's easier to blame an outside source than our own decisions. Anything that resultsin lots of damage to the canopy is not 'natural' or 'good' - though, some damage can pop up, but it should be minimal in severity.

a leaftea from healthy leafs could solve most inbalance problems - after flushing the soil.

DWC? Not enough info, give a lower feed if dwc

Yeah typical clawing from nitrogen, The TA tri part is a really good system mixing different ratios of all 3 to balance the grow. I guess you have overdone it and probably squed the pH also I would advise to give only water and use up some of that salt build up to feed try get run off if in soil and defo get run off in coco atlradt 30%. It's only stunted not dieing she will be back on track soon enougj