Cycle Question

You already have a strong base with your training, nutrition, sleep, TRT, and regular bloodwork. Just be careful not to change too many things at once.
Because you’re on TRT, you’re right that you usually wouldn’t do a traditional PCT, since your body’s testosterone is already being replaced. Most people just go back to their prescribed TRT dose after a blast, as long as that’s been cleared with their doctor.
About Deca, I wouldn’t jump to blaming your AI. Nandrolone can affect mood differently than testosterone, and some people just don’t handle it well, even if their estrogen is in check. If you felt depressed or emotionally flat before, take that seriously instead of thinking it was just life. If you try it again, it’s better to start with a low dose and pay close attention to how you feel, rather than increasing the dose quickly.
About the "cat pee" smell, I’ve heard people mention odd body odor changes while on AAS, but it’s not a normal or expected effect of nandrolone. Things like hydration, diet, supplements, or even another medical issue could be the cause. I wouldn’t expect milk thistle to fix it. It’s mostly sold for liver support, and there’s no solid evidence it changes body odor.
One tip I’d add is to change only one thing at a time. If you increase your testosterone, add nandrolone, and then later try Anavar, it will be much easier to see what’s causing any benefits or side effects. This also makes your bloodwork easier to understand.
Good luck with whatever you choose. Remember to watch more than just your lab results. Your mood, blood pressure, hematocrit, and overall well-being matter just as much as the numbers.

Ethan made some solid points regarding the psychological impact of Nandrolone, but I want to address the two "elephants in the room" that often get overlooked in these TRT-plus-Blast conversations: the DHN issue and the metabolic origin of that "cat pee" scent.
Regarding the mood and "emotional flattening" on Deca: it is often not just an estrogen or prolactin issue. Nandrolone converts via 5-alpha reductase into DHN (dihydronandrolone) rather than DHT. DHN has a much lower affinity for the receptors in the central nervous system. When you run Deca, you are effectively displacing the "feel-good" and "drive" signals of DHT with the much weaker DHN. This is the biological root of the mental fog and the infamous Deca-dick. If you are going to run it, keeping a higher Test-to-Deca ratio is essential to maintain enough DHT to keep the lights on upstairs.
As for the "cat pee" odor: that is a massive red flag for nitrogen clearance issues. It usually happens when the body is breaking down excessive amounts of protein for energy or when the kidneys are under significant strain and ammonia is being excreted through the sweat glands. Milk thistle won’t touch that because it is a renal and metabolic load issue, not just a liver enzyme spike. Check your hydration and, more importantly, your Urea and Albumin levels in your next labs.
The "change only one thing at a time" rule is the best advice in this thread. If you don't track the variables, you are just a passenger in your own biology. Stay safe and keep the data clean.