plus it is always good to have a spare for testing purposes or if your 4090 needs a warranty repair, etc.
I really think you should upgrade your audio experience though, that is the weakest part of your setup. @VSG
could recommend you something based on whatever budget range you are willing to spend in that category. I'd say the HifiMAN Edition XS at $499 and this for your headphone amp - not sure on the amp though.
I think you would impressed by the increased immersion you would get