Although the Noctua is a good cooler you will not be able to run a stable and significant overclock on the PC. My recommendation would be to drop to a 9700 (non K variant) and include another 2 sticks of ram for a total of 32gb, and add a 1tb SATA SSD. Also, the improvement in terms of performance in RAM clock speeds drops off a cliff after 3200mhz. Anything after that point is just to say you have it. To summerise:

I7 9700 with Noctua cooler or 9700k with AIO watercooler to overclock for future-proofing. The 9900k is a VERY good top of the range CPU but it would be unlikely you would be able to use the full amount of threads in tasks because software programs have not caught up with the times and windows is a bit poopy too. Either of my mentioned configurations would be more than plenty for the tasks described and save you some money for peripherals or anything else you require.
Same GPU as on list
32gb of 3200mhz RAM
Same NVMe SSD
Add a 1tb SATA SSD for bulk fast storage, the cost difference in SATA SSD's compared to conventional HDDs is so minimal now there is no point unless its for archival server storage.
Case looks good for airflow and cable management but I have never heard of it.
I don't know enough about motherboards to advise but that one looks cool.

I run a 9700k with Corsair AIO watercooler and an RTX 2070 with 16gb 3200mhz ram 1tb NVMe SSD and 1tb SATA SSD. Arma runs perfectly well enough CLOSE to stable 60 in and out of ops here. Other games, for example the new Call of Duty Beta, I was running comfortably at 1440p 120fps on my 1440p 144hz monitor. With the budget you have, you cannot go far wrong and either way, you will have an amazing system. Just remember, because you have that budget doesn't mean you HAVE to spend it all but your money so you do what you very well please with it. I just wish I had that budget!