Happy Holidays!
You have a few ways to go.
1) Signburst.com (as others have mentioned). Having support on deck is golden. Especially if support is handled by the same guy that put together the machine. He is a member here. Great, patient, guy. I'm still running a version of his signburst-inferno I bought around 2010, I think. Also, he is familiar with the Sign/Graphics Industry. Not just a geeksquad tech. (No slight against those guys)
2) Pugetsystems.com - Systems built for your specific needs. Tailored to get you the most power for your specific use case.
*3) Research and build yourself: Its a really weird time right now for cutting edge hardware. But you can find really good deals on current/last gen tech and get a great system built in no time. Can't say it enough though: DO YOUR RESEARCH. And then, DO IT AGAIN. And again. Try not to fall too far down the rabbit hole. Get what you need. Commit to the decision. Build it. Go make your money back. Rinse. Repeat.
There are a ton of great virtual system builders that will compile and price systems for you based on a couple tick boxes. Pros and cons to each. But if you DO YOUR REASEARCH, you will be fine. I like PC Part picker. First because I'm familiar with the site. And Second, there is an active community behind it that shares opinions, experiences AND photos + step by steps notes of their builds. Very valuable.
Here is one I built with my son this weekend.
https://pcpartpicker.com/list/wYKBht Ignore the prices because I am a sale hunter. And for some stuff I might pay more because its available right now.
Some additional notes for you:
Everyone is going to have an opinion about this and that. There are only 3 that matter. Yours. Your business'. And your wallet's. (Well there may by a wife or an accountant in there some where)
Right now, current gen GPUs are like Silver and Gold during the rush. You may have to bash the scaplers with your shovel to get new tech or settle for last seasons tin. Do your research and that analogy will make sense.
And lastly, Gaming PC
≠ Design PC (It can be. But its not the end all be all.)