I see that I got too carried away by my own taste when replying to your post, and missed the important criteria you have stated. Sorry about that.
No problem!
You did help me quite a bit. 
So I did more online browsing.
I checked Amazon for office chairs and gaming chairs at any price.
There are very few office chairs with a footrest like I'm looking for, so I checked Walmart, Target, Office Depot, and Best Buy for gaming chairs.
(I already checked Staples.)
I didn't find anything that I was looking for.
By the way, Amazon seems to be the best place to shop for gaming chairs, if you're going for sheer selection.
The chair that appeals to me the most is the one I ordered. 
...
Also, I forgot to mention:
I want a chair with wheels and adjustable height.
I checked Overstock for gaming chairs.
I didn't find anything I like.
I received the skunk chair today.
It took me an hour and ten minutes to put it together.
I was taking my time and looking at the instructions a lot.
It came with a lot of pieces to put together, and it intentionally came with some spare parts.
I was able to put it together correctly on my first attempt, but it was much more difficult than when I put my office chairs together.
I've only been sitting in it for a few minutes, but it seems decent.
I don't think I'm going to try to return it.
Despite calling it a "skunk chair", luckily it doesn't stink.
It seems to be made of quality materials, though I don't know how long it'll last.
I'm hoping that the next time I'm looking for a chair, I can find an office chair with a footrest.
That is a very rare feature (right now) in office chairs.
EDIT:
By the way, the chair is not made for people with wide hips.
I'm kinda skinny, and I fit in it fine, but I could see how it would be a problem for wider people, even if they weigh less than 300 pounds.
By the way, the support/cushioning seems much better than my office chair.
I mean, the office chair cost only $50-$60, and this gaming chair was about $150, but it is a nice improvement.
If you did return it, would you have to disassemble it ? Doesn’t seem feasible.
I think I could disassemble it if I needed to, but I really don't want to.
The chair seems nice enough to keep so far.
Good luck with it.
I read a lot of customer reviews on Amazon for gaming chairs, and I read a lot of horror stories, so I'm very glad that so far I can live with this chair.
I received a PM from G0OSE in which he recommended this back cushion for chairs:
https://www.amazon.co.uk/Hardcastle-Memory-Foam-Back-Cushion/dp/B017NPL2WE
I thought that was excellent advice, but that particular item isn't available on American Amazon.
That is not a problem because I prefer to do my own research, and I picked out a similar product:
https://www.amazon.com/Wheelchair-Cushions-Adjustable-Sciatica-Breathable/dp/B07ZB9VL5X/
The item I picked out is way pricier, but it had the best feedback on Amazon for a "two pack" so I'm okay with it.
I really don't know what I would do without Amazon.
They're great for customer reviews, and sometimes they have the best price as well. 
Over 300 pounds you need a forklift not a chair.
There are gaming chair for larger people, but I hear that they are usually/always quite expensive compared to the smaller chairs.
About the skunk chair:
The make and model are GTPLAYER GT800A.
The American Amazon page does not have the model number, and the chair is not available for purchase from there right now.
The only other place that sells this chair (that I can find) is Canadian Amazon:
https://www.amazon.ca/dp/B083FSYMGN
I don't know if they ship to the U.S., and it's more expensive to boot.
They have it in all four color schemes, and the customer feedback is not nearly as positive as on the American Amazon site:
https://www.amazon.com/GTPLAYER-Gaming-Footrest-Ergonomic-Massage/dp/B08332K9XN
Also, on Canadian Amazon, the chair is branded as GTRACING.
(GTPLAYER and GTRACING are two different names for the same company.)
I ordered these armrest pads:
https://www.amazon.com/EcoLifeDay-Pressure-Furniture-Accessories-Increase/dp/B07J3N34CB
I don't think they'll be that great, but they were the best that I could find for my chair.
I screwed up...
I cancelled my order for the cushions, to order the same cushions along with the armrest pads, to get free shipping for everything.
When I cancelled that order, I lost Amazon points that I had earned by using my Amazon credit card.
I wasted something like $9.89
Never cancel an order if you use Amazon points because I don't think you'll get those points back.
You do get them back. When you get the refund email it will show the breakdown. Probably doesn’t show up until next month.
My payment method never got charged because the item didn't ship for the cancelled order.
Oh, so it takes a while.
Thanks!