High end graphics is not necessary - you won't see much difference between a middle of the road GPU and a high end "gaming" card. PS and LR do not use CUDA technology, and you only need enough memory to display your image at the resolution required for your display. Anything more is a waste of money.

https://www.pugetsystems.com/recommended/Recommended-Systems-for-Adobe-Lightroom-Classic-CC-141/Buy_158

https://www.pugetsystems.com/recommended/Recommended-Systems-for-Adobe-Photoshop-CC-139/Buy_150

A compared to a high end, $800 RTX 2080, Ti, a $170 GTX 1060 is only 8% slower. Spending the extra $630 is not a good way to spend money on a system for Photoshop. The game changer is if you are looking to get 30 bit color - in which case you'd have to buy an NVidia Quadro or a AMD FirePro.

And you can have a wonderful experience running a $3000 PC vs a comparably peforming $5000 iMAC Pro.

I agree that you don't need a gaming level graphics card, but you do need a good one with some extra memory. I'm a heavy Lr and occasional Ps user. My iPad Pro flies! I came from the PC world as well and switched to Apple about five years ago. I still maintain a PC system or two, but I, far and away, prefer Apple. I gladly pay an extra 2k just to keep away from Microsoft's weekly updates and have a system that really is plug and play.

I've been supporting both platforms for years - and at this point, ever since Mac went over to Intel, there is so little difference between the two platforms - that the extra cost is hardly worth it - especially since you don't get any more bang for the buck. As I have said over and over again - the only meaningful difference between the two platforms is cost. Of course, if you are doing color critical work - the workstation of choice is the RGB-based PC, and not the DCI-P3 based Mac - at least as far as wide gamut color is concerned. Corporate graphics departments allow the use of just about any computer for setup and roughing, but for final, precise color work, the PC reigns supreme. . . just sayin'

For video production, I much prefer the Mac, btw. Final Cut Pro is excellent software, and the way Avid works on a Mac is pretty sweet compared to the PC implementation. Premiere is pretty good on Mac, but slightly better on Windows.

16 GB RAM (32 GB if you want to run multiple apps and switch among them)
Quad Core i5 or better
256 GB SSD or larger
1 TB or larger 7200 RPM external drives, minimum 2
Accelerated graphics if available
27" 4K monitor (2 if you can swing it)

If you buy an iMac, get the 27" so you can upgrade the RAM by yourself. Buy minimum RAM and source larger modules from a third party.

Remember, most Macs are expanded EXTERNALLY. They have fast Thunderbolt 3 or USB-C and USB 3.1 connections for attaching drives, scanners, networks, monitors, port breakout boxes, expansion bays... That way, when a component fails, it is less likely to require sending the Mac to an Apple service center, because it might be an external component.

PC users typically hate that, preferring an open box with a giant power supply and noisy fans. Pay money, take choice...

DO NOT forget to buy a monitor calibration kit from Datacolor or X-Rite.

Steve,

Welcome to the forum and the wonderful world of photography.

My baseline recommendation regardless of whether you purchase an Apple or some other PC are the following:

RAM: minimum 16GB, more the better
Processor: Intel i7 minimum
Internal drive: preferably a SSD (solid state drive) but if not, then go for no less than a 7200 rpm spindle drive.
Video card: preferably dedicated (typically Nvidia)

As for editing software, the Adobe Photography Bundle for about $10/month is what I use but the are others who are more familiar with some free software.

Steve,

Welcome to the forum and the wonderful world of photography.

My baseline recommendation regardless of whether you purchase an Apple or some other PC are the following:

RAM: minimum 16GB, more the better
Processor: Intel i7 minimum
Internal drive: preferably a SSD (solid state drive) but if not, then go for no less than a 7200 rpm spindle drive.
Video card: preferably dedicated (typically Nvidia)

As for editing software, the Adobe Photography Bundle for about $10/month is what I use but the are others who are more familiar with some free software.