Pardon my ignorance but the drive bays are the little white plates in back I unscrew to put the video card through correct?
No. What you are talking about, are PCI covers. Those, 3 of them, you have to remove regardless since GPU goes there.
Drive bays are on the front of the PC case.
These 8x white ones, used to hold 3.5" HDD (or 2.5" SSD);
Direct link if image doesn't load:
https://www.fractal-design.com/app/uploads/2019/06/Define-R5-Black_2-810x810.jpg
Source:
https://www.fractal-design.com/products/cases/define/define-r5/black/
I have no issues taking a few off as long as it doesn't leave a giant open hole we are good.
You may need to remove 2-3 drive bays (aka caddy) to fit the GPU between them.
Also any recommendations of places to buy them from? I know of newegg. Amazon has a lot but I never know how to tell if they are Brand new sealed packaging or refurbished on amazon seems like a lot of them are refurbished third party sellers.
Since TH is international, we usually let people to choose their own source where to acquire the hardware. E.g i live across the pond, in Europe and folks here, do not have access to the Egg at all. Amazon is primary source for us + local, national stores.
I guess you live in USA. Besides Egg and Amazon, there's also Micro Center. I've head from our overseas folk that Micro Center can be trusted. BestBuy should also carry PC hardware. But i can not access BestBuy at all, since their site is geolocked to USA only.
So, if you trust Egg, sure, buy from there.
I have two screens and I like to game on one while watching 1080p stream on other monitor if that helps in any way.
Well, not much, since you didn't tell on what reso you are gaming on. 4K? 2K (1440p)? 1080p?
You only told that you like to look 1080p stream from 2nd monitor.
But it doesn't matter.
RTX 4070 Ti can do;
~145 FPS on average on 1080p (~95 FPS when Ray Tracing is enabled),
~118 FPS on average on 1440p (~62 FPS when Ray Tracing is enabled) and
~69 FPS on average on 4K (~32 FPS when Ray Tracing is enabled).
Review:
https://www.tomshardware.com/reviews/nvidia-geforce-rtx-4070-ti-review-a-costly-70-class-gpu/6
Of course, it all depends on game. Some games have higher average FPS (CPU bound), while others have lower (GPU bound). But it is considerably better than your RTX 2080 Ti, so you can expect FPS increase.