SLOW GROW AND "BURN" LOOK

First off, 14hrs light is fine, it will grow, If you provide the 40 DLI in that time span "upper limit DLI cannabis can use without artificial CO2 supplementation" its more then enough, even if its under that 40 mark its good eg 30-35. Autos can tolerate lesser amount of light and grow well. Look up DLI if this is new to you, in short its the amount of light and its intensity based over the course of time and reduced to a easy number. Might be butchering it a bit there but it gets the gist of it. eg you can have 40 DLI over 12,14.18 or 20hrs, hell even 24hrs. But its good to give plants rest. I do 18/6 on autos but if I need to save on hydro I'll do 12/12 or 14/10 like your doing and run it in the off times when rates are lower, maybe your hydro rates vary like mine maybe not, does not matter the plants will produce. Secondly, From what I can see you should not be using just Sugar Royal, its NPK is 9-0-0 according to the official site, but only 1.96-0-0 on GrowDiaries product page... so IDK. grain of salt with that. look on the bottle itself to see if it references a NPK value and go off of that number. You need the main fertilizer in that setup Alga Grow to give the plants a more well rounded fertilizer. This snip it is from the site on how to use Sugar Royal: >>As always, give the bottle a shake before opening it. Add Sugar Royal to your nutrient solution at a rate of 1ml per litre of water. Start using Sugar Royal from the second week of the growth stages, using it every time you water. Sugar Royal is not suitable for hydroponic growing systems, as it can cause blockages. If you are running an irrigation system, flush the pipes after use.<< If you follow their grow guide it starts with the Grow Nutrient. Alga Grow and does not introduce sugar royal at all, but sugar royals own directions say after the 2nd week of growth. https://www.growbarato.net/blog/wp-content/uploads/2019/07/natural-grow-schedule-us_page-0001.jpg Or reference the chart in their catalogue with all their products. https://plagron.com/downloads/en/catalogue I don't like a lot of Plagrons feeds or mediums, the coir feed is ok and well rounded by not concentrated as much as I'd like to see, and all the other options I find have holes and gaps. Also no idea what your growing in. but it may cause some issues down the road as it does not look very aerated, and if it is void of nutrients its need supplementation or if it needs microbs to break it down the amendments in it to become available it could be overloading it in time as they break down more and more. Side note if its any of their branded mediums, they are all coir or peat based, nothing is truly soil by definition. has some aspects of soil like compost or castings but lacking others. Good Luck!