It would be cheaper to build your own. So what i would recommend would be to talk to any of your friends who may be in IT or knowledgeable or go to a pc shop and tell them your budget.
Honestly I would build it yourself since they usually tend to use cheap psu's on pre builts, trust me they are making hard profit somewhere lol. Building is easy and people can help you on here make a nice build
If you're up for something new I can recommend that at this point you should just build it yourself. I knew nothing about computers or anything electronic and one day I decided to just order it piece by piece, saw a few video tutorials online and just put it all together, was much more simpler than I thought.
That way you purchase the exact components you want and don't have to pay an extra 300-400 bucks for a prebuilt.
I'm sure amazon will have a better deal come cyber Monday or hell, even check out newegg or pcpartbuilder. Can buy it part for part and be cheaper but at same time, if you buy it prebuilt, it's going to be more but put together professionally
But what monitor are you using ? This system won’t mean anything if you have a 1080p monitor, would be like sticking a powerful supercar engine inside a Toyota.