Have you tried upgrading your RAM to 32GB since you're streaming? Maybe that would fix some of the issues during your stream?
I can only say from personal experience that upgrading from 16GB to 32GB did help, especially on 1080p @ 60Hz/FPS streaming with XSplit Broadcaster. I currently use 5800X, 32GB and RTX3080. Display is at 1440p @ 144Hz but I run my games at 1080p @ 60+Hz.
https://pcpartpicker.com/list/YhNm68Also, make sure your streaming codec is on your CPU and not GPU. Yes this will put the stress on your CPU rather than your GPU. During streaming, my CPU usage goes up to 50-60%. If you have a good enough CPU cooler, perhaps you can overclock your Intel 9700K.
I do think a 5900X or 5950X is overkill for streaming but at least it'll be powerful for the future years. I periodically watch other random streamers and from my personal recollection, these small time streamers are running a Ryzen 5 or Intel i5, and they're at 1080p.
I think im just going to go with a cyberpowerpc tbh, It seems like a really good option + i have a friend willing to buy my current pc for 700$