I presume the images are all at 800mm? I gave my 200-800 an extensive work out on a trip to Goa last November/December and I found that the images are definitely softer at 800mm than the 100-500 at 500mm. This might be partly due to the heat distortion but nearly all my images probably need a bit of sharpening in PP which you appear to have done too? The clarity of the image is even more obvious at 100% with the 100-500 still retaining more detail. No doubt in my mind which is the better lens and the one I'd keep if I could only have one of them.
Interestingly though I have barely touched my 1.4TC since I acquired the 200-800. I only have one camera body at the moment, an R5Mk2, and if I need extra reach it's easier to swop lenses than add a TC if I have them both with me.
They all have a bit of sharpening, but in that respect, so do the images I take with the 100-500. I believe shooting in Raw means that sharpening is always needed, simply because the image is not subject to the in-camera sharpening that jpegs are. I try to use the extra reach of the 800 to increase the size of the subject in the frame, rather than to increase the range, because we can't fight physics, and longer shots are always going to be softer than closer ones, simply because of the extra air between the lens and subject. Heat refraction is another menace that not much can improve, apart from not shooting on sunny days and avoiding 'ground-grazing rays' when possible. Extra reach simply makes its presence more obvious.
When my R5ii arrived last August, I was just 4 days away from my annual raptor migration trip. For the past couple of years, that has meant my R7 with the 100-500 for the thousands of birds, and my R5 with the 24-105 for everything else, simply for the extra reach of the crop R7. In 2024, I replaced the R5 with the R5ii on the trip, and intended to use the R7 for the birds, as usual.
When I got there I naturally wanted to give the new camera a try, so on the first day I used it with the 100-500 +1.4x to give it a run out. My 200-800 stayed at home for convenience. I find the 800 is just too much reach for tracking a flying bird with the crop body, particularly in a strong wind, as there almost always is a Tarifa. I was blown away by the new camera, and the R7 stayed in my bag for 10 days until I used it to photograph a tern roost at range on an estuary and again about a week later to use the tighter crop on a Ruppell's vulture on a cliff ledge. I came home with about 9000+ shots on the R5ii and only 600 on the R7.
I envy you your Goa trip, we were last there in January 2018 and I'd love to go back with the new gear.