For the CPU, 6 cores seem slightly too little, get something with at least 8 cores. I've got a Ryzen 9 5900X with 12 cores, since I thought I'd be doing stuff like video editing and playing very intense games. I don't use all of my cores like 90% of the time so it's a bit overkill.
For a CPU Cooler and fans, use Thermalright instead of Noctua. They tend to be cheaper and better.
Also do you really need 240hz? 144hz should be smooth enough. Even 120hz should be good.
For the mouse get the VXE R1, it's probably the cheapest good gaming mouse on the market right now.
For headphones, if you don't need a mic I got the AKG K92's and they sound like shit but the soundstage is amazing. Once you apply EQ to them though, they sound great though the bass could be better. I broke mine so decided to get the Soundcore Space One, which are extremely good for the price (not sure how good the mic is). The soundstage is slightly bad though. The Sony WH-CH720N is better than the Soundcore but it's slightly more expensive so if you have the money get the Sony headphones. Gaming headphones tend to be a fucking scam, you basically only pay for the RGB while getting shit audio.
For the case I can recommend the Corsair 4000D airflow. The airflow is really good. But that's an ATX one, it might be too big for you.