It so happens I recently took a Pixel 6 Pro and a Canon 80D on a trip abroad. I used a rebuild of the stock camera app that does away with the automatic over-sharpening that the stock camera app has, and with the 80D, I used the EF-S 15-85 mm lens that (I believe) used to be the kit lens for the 7D. I also used the EF 70-300 mm non-L lens.
There is, in my opinion, no question that the 80D takes sharper pictures in daylight. It's just hard to beat a sensor that's that much bigger. The lenses, also, just have way, way more light gathering power.
Now, in dark places, at night, I used the P6P more, and that worked better than the 80D. But I'm glad I had the 80D for the big landscape shots and for the tight shots of people's faces.
The A7 III is way lighter and smaller than the 80D, and takes way better pictures. I would suggest considering finding a space for it in your bag. At least take a few pictures with both the P6P and the A7 III and view them at 100% to see if you're happy with the results.
If you're willing to post process your images, the 80D will look way better for night pictures.
The problem is that there is no built-in function for it and you have to manually process each pictures. You might even need more than one tool if you want to take advantage of the same type of AI fakery that phone have.
One thing I love about my A7S is the ability to tilt the screen and take candid photos of people while we're having a conversation. Also that thing pretty much shoots in the dark so I find that magic.
I regret not buying a Sony when I got my Canon 6D. Almost all of the lenses I use now are old/vintage and it sucks not having image stabilization for the extra 2 stops and a digital viewfinder to properly focus the lens. I almost resold my 6D many times in the past but I got too attached to it to ever pull the trigger.
There is, in my opinion, no question that the 80D takes sharper pictures in daylight. It's just hard to beat a sensor that's that much bigger. The lenses, also, just have way, way more light gathering power.
Now, in dark places, at night, I used the P6P more, and that worked better than the 80D. But I'm glad I had the 80D for the big landscape shots and for the tight shots of people's faces.
The A7 III is way lighter and smaller than the 80D, and takes way better pictures. I would suggest considering finding a space for it in your bag. At least take a few pictures with both the P6P and the A7 III and view them at 100% to see if you're happy with the results.