" I understand this might be subjective, but I was expecting a bit more from the camera 3x the price of t3i so that's why I'm a tiny bit disappointed."
If you expected a 3 times better photo you are going to be very disappointed. Every time! Improvements in DSLR tech is already advanced to where improvements come in slight to very slight increments.
I looked at a few of your samples.
"...jpg imo t3i looks better even on big screen and definitely better on LCD of the camera."
This you can not do. 
The LCD may be set brighter and it is the LCD you like better, not the photo. Same for your monitor. Keep in mind you can not view a Raw file. It has to be converted. How you do that and by which converter you use can affect the resulting jpg by a lot. Conversely, when you shoot in jpg your camera converts the Raw file in its conversion routine. I think you are confusing "brighter" with "sharper". It is a common mistake most people make.
I would encourage you to do some research on post editing as it could be how you are doing it. The ability to edit in Raw far exceeds what can be done with a camera converted jpg. The 80D has very much more room to do these adjustments over an T3i.
Besides the IQ improvements in the 80D keep in mind how many other features it has like wi-fi that cause a price increase but has nothing to do with IQ.
@yteln wrote:Sure, you can see a comparison here: https://drive.google.com/drive/folders/161b7JrLDXR5ed7yS6oUAWu_4RyMIK1fj?usp=sharing
I was focusing on bananas, 3 bottles of water and a guittar respectively. E.g. if you look at bananas t3i is clearly sharper. Of course there are also some photos where 80d wins (not by much) but overall I'd say it's a draw or the difference is tiny on CR2. On jpg imo t3i looks better even on big screen and definitely better on LCD of the camera. I understand this might be subjective, but I was expecting a bit more from the camera 3x the price of t3i so that's why I'm a tiny bit disappointed.
If you lift the shadows in a raw converter you will see that 80D has much less colour noise than t3i has. 0095.CR2 vs 1044.CR2.
About focus it seems like 80D and your lens are front focusing (Micro adjust it later). You should start with Live view. Then 80D and t3i will set AF without issues in Live view. Is it an old Sigma lens or Tamron lens?
The image below shows dynamic range 80D (IMG_0097.CR2) vs t3i (IMG_1046.CR2).
OK I apologise right up front but remember you asked!
There is no lens correction in PS for a "yongnuo 50mm f2" lens. It is junk. Get rid of it.
I d/l the first two of the guitar photos from each camera, The 80D and the T3i. I stopped right there because both are so far out of focus to be unusable. Or the lens is so bad as to be unusable. There is absolutely no way to compare these shots.
For any meaningful results form either camera you need to get a decent lens. Even the cheapest kit lens will do better than what you have. A best buy lens you might want to consider is the ef 50mm f1.8. At any rate shown is an example of the corrected editing in PS of one shot. Other than extreme OOF you can see it is a pretty nice photo.
"I have found that a properly focused image from the Kodak DC-290 compact I bought to take to Cuba in 1999 looks better than an OOF image from my Canon 1DX 2 and EF-200 F2.0"
One thing LR/PS won't correct or fix is OOF. Oh, yeah, they have attempts but still pretty bad. Bad is bad usually and sometimes you can't fix it. I did not d/l any of the others because I saw these two as a waste of time. My PS/LR doesn't have lens correction for the lens used but I can't see it helping anyway.
Anyway happy holidays! 
@ebiggs1 wrote:We got 9 inches of snow. I ain't going outside unless I absolutely have to. Can you tell?
You should be out capturing a snow scene for your town's 2021 Community Calendar.
