Advise welcomed for newbie

Take my advice with a grain of salt because I'm not really a master grower. If you wanted to continue the grow until completion, I would flush your plants with just PHd water. If you are concerned about overwatering, point some fans at the fabric pot to get the soil to dry a bit quicker. The biggest issue you have looks to be pretty bad nutrient burn as well as a nitrogen toxicity and possible nutrient lockout due to the amount of salts in the soil. It also looks like the plants are suffering from heat stress. If you were to do everything right from now on and immediately fix the stress the plant is going through you may end up with a small harvest. If not you may just end up with a few nugs. Its good though that you're doing this because mistakes are blessings in disguise that help you grow both literally and figuratively. Everyone has their first grow and there is no shame in taking agency to improve as a cultivator. Next grow (assuming you are running autos again in Happy Frog) I would just focus on growing the plant feeding only PHd water for the first 3 weeks of the grow. Autoflowers don't typically need a ton of nutrients and for the most part they can get through veg with very little npk. The ideal is to feed just the right amount of nutrients to avoid nutrient deficiencies at just the right times but doing that is really hard (and strain dependent) so the best alternative is to underfeed and then deal with nutrient deficiency as soon as you notice it happening. The reason you want to do this is because salt based liquid nutrients are immediately available to be taken up by the plant you so can fix deficiencies almost immediately whereas you don't want to be put in a situation where you're forced to fix a nute lockout. If you don't notice any nutrient deficiencies after 3 weeks of growth then I would start feeding nutrients at 1/4th the recommend dose every other watering. In early flower your ratio of veg nutes (N) should be a bit higher than your flower nutes (PK) with you progressively reducing the veg nutes as flower goes on and only feed flower nutes. If you start noticing your plant having deficiency issues with the 1/4th nutes then you know for sure you need to up your dose which will give you an idea on how much to feed and when without causing burns or lockout. Hope this helps and I wish you luck with this grow and your future ones :D.

shout out to dude writing a short novel for the answer

Way to much food.

Going to jump back in here to say a couple more things .... the leaves that are curling up on the edges are telling you it's much too hot for them or your lights are much too close (which would also equal being too hot).... the leaf at the top of the picture here is showing one of two problems - it's either been burned by your lights (which would make sense given the curling edges on the other leaves) or you're getting a nutrient deficiency which is most likely caused by either overfeeding nitrogen or the pH. I'd want to see another picture (STILL picture, not video) in a couple of days to see what the progression of this is in order to be able to give you advice on what to do about it...

Ok. Let's start with your misconception that you've overwatered. Overwatering is the state of being constantly wet - it is NOT the amount of water you give at any one time... They probably, given your comment in your diary, were underwatered for a period. Now let's tackle the overfeeding. Yes, and you're doing it MASSIVELY... Any and all feed charts from nute lines will give you dosage recommendations but they're specifically addressing photoperiods which can take much more nutrients than autoflowers can. Autos are terribly finicky and I've yet to grow one (and they're all I grow) that can stand full doses. When you grow autos, you want to wait until they're about a week (or even better 2 weeks) old.. and then you start them off VERY slowly with about 1/4 - 1/2 recommended doses to see how they're going to react. If they are ok, you can GRADUALLY increase the dose but again, they'll never be able to tolerate a full dose. For these girls, I would suggest you give them nothing but pH'd water for at least a week.... and btw, I don't know how you're measuring EC but there's no way your nute solution is reading 0.5 ... maybe 5.0 but not 0.5.. If you can measure your ppm, the equation to calculate EC is (ppm*1000)/2 ... And now we come to pH. Your pH is too low for a soil grow. You need to bring this up to a MINIMUM of 6.0 - 6.2-6.3 would be perfection. If you don't have one and can afford it, one of the best tools you can have as a grower is a good pH pen... when I was finally able to buy one, it dramatically improved my grows and eliminated a lot of problems I'd been having. I applaud you for sticking with this grow because it WILL give you a harvest and you WILL learn a ton during the entire run. I messed up massively on my first grow as well so don't beat yourself up... I got a good harvest out of my first one - nothing that experts would think was worth the bother but it was worth it to me... and I learned! Conditions and the health of your plants can change at a moments notice so it's not good not to at least check on these ladies at least once a day... Problems/deficiencies/toxicities take a while to actually show up in a soil grow and take even longer to be able to cure them (deficiencies are a helluva lot easier to fix than toxicities). Make a practice of at least eyeballing them once a day (I like to take daily pictures and post them in my diary - really helps you see the growth and see problems early on). Final thought here... with autoflowers, less is more. Less nutes, less stress, sometimes even less fiddling around... they've got their own time schedule they need to keep to and all they ask is the right nutrients at the right time, the right pH, and sufficient water .... they're wonderful for getting a quick harvest but you really need to treat them right.. Good luck - keep with it - it WILL get better and easier the more you learn!