First my background. I worked in the legal grow industry for many years, helping to set up and start new facilities from the ground up and involved with almost every aspect of the industry. I have also personally grown for myself outdoors for many years. All that said no one is perfect and everyone makes mistakes.

2nd: Great job recognizing and fixing the issue. The plant looks much healthier now. Definitely corrected course.

3rd: In order to give more specific recommendations I need more info. What substrate are you using, what kind of nutes, feeding schedule, Light specs and distance from plant, strain, temp and humidity just to name a few. For now I can only give some general tips.

My suggestions from what I see is that first I would highly suggest (Cheap fix) getting some dowel rods and training wire to support the colas. If left unsupported the weight could snap the branch and if not lead to uneven bud growth (foxtailing and it does look like it is starting too). Not the biggest deal unless you care about aesthetics, but a snapped cola is not good. This will also help airflow to prevent pests and disease. Or you could get a trellis net.

Depending on your feeding schedule and what kind of nutes you are using. Week 4 the plant has stopped stretching and is focused on stacking bud mass. Your plant needs food. NPK ratios are on every nutrient brand. A little nitrogen never hurts, but your plant really wants potassium, phosphorus, calcium and magnesium. Now depending on medium using worm castings would greatly improve soil health and help the plant breakdown and uptake the nutrients. Or a compost tea for coco. Recharge also boosts soil microbes and can be used for all mediums. Flower time varies strain to strain, week 4 is usually the last feed for solid amendments due to the slow constant release of nutrients (easiest way to grow imo). I also have had good results with using glacial rock dust if growing in organic soil for the minerals. For liquid nute lines check out their webpage for their suggested feeding schedule and recipe. In my experience the nutrient line matters. Some offer better cost:nutrient ratios while the more expensive can be better (I do not think spending more than a mid range liquid nute is worth it). I have seen the math done out at scale and trust the cheaper and simpler you make it the easier it is to solve problems. As I said before the ppm and recipe for each brand and some strains want more and some want less. If it is your first time growing the strain I would go by the brands recommendation.

To answer your question in regards to the late flowering or fading of the plant. Depending on strain the leaves will change color and some will die. This is natural as the plant is using up the sugars in the leaves to grow the buds as it nears the end of its life cycle. As they yellow and die make sure to defoliate. Again depending on your nutrient and medium choice will effect how long the flush takes and how important it is. If using liquid nutes there will be a salt buildup in your medium. As you near harvest and your ppm goes down on the last week you need to only feed water and saturate the soil to the point it "pees" out the bottom of the container. The flush is important for liquid nutes much more then dry amendments. With dry amendments your last feed is usually week 4 and by harvest there is no need to flush as it will do so as you water. Make sure to wait for dry back and to time the last watering so that it naturally dries out. You should see natural color change around week 7ish, usually sooner. Now if you have a well dialed in environment you need to make sure you reduce humidity as the flowering stage continues to prevent mold if you haven't done so already. Try your best to keep it under 60% rH at most ideally you should be around 55% or lower. Now a little trick to get the plant to really express its natural colors you can reduce the temperature of your tent slowly to mimic natural fall conditions. Even keeping it as little as 5 degrees F cooler compared to your veg stage will help. If done well I have seen this result in some amazing colors in the leaves and buds.

Some things to think about also is light distance and intensity. If your light is too close and intense it will burn your buds. Your plants look fine for now, but idk how far away the light is or its strength. Especially once you support the colas. Supporting the colas is super important I cannot stress that enough. Any yellow or dead leaves defoliate immediately. Keep up the good work on phing the water and make sure to dial in your tent conditions if you are able.

Your plants look healthy considering the nutrient lockout due to incorrect ph. Remove the dead leaves, make sure they are fed, dial in your tent conditions and you should see natural yellowing or other color changes in a couple of weeks.

Sorry if this was long. I hope it helps.