I'm not that invested and I also can't stand flying. I'm not trying to proof anything, I am asking for proof.
So far I have one map and real time radar (I forgot to include the source info in my last post its here : https://www.flightradar24.com/QFA28/3c5063e0 ) and both of these line up with the claims of the global map.
You made an argument I can't verify where you claim that the flight speeds are being manipulated. Ground radar is a thing, theres networks where plane spotters use their own radars to track flights as well, its called adsb. Theres another website called adsb exchange where that data is combined available here https://globe.adsbexchange.com/ but since thats hobbyist ground radar it won't show you intercontinental planes as those will be out of range. Still, these can be useful if you wish to validate the flightradars website speed measures for yourself.
Now I am open to the earth being flat, one explanation could be that the polarization of the earth is not equal to the middle point and that there is another map that lines up if we take south america as the middle point for example. But i'd wanna know which map that is before I believe it. Because for me personally a grand conspiracy that every plane and plane tracking system in the world is rigged is to unlikely.
If you want to find out more about the adsb software to check it for backdoors you can probably use https://github.com/rickstaa/awesome-adsb as a starting point.
Gives you a few feasible paths to proof your theories to me i'd say as you can find a more accurate map, find the backdoored code on github or find planes where adsb's open data is different from flightradar24 in ways that proofs your speed spoof theory.
Either way even if we disagree in the end I hope you find that my arguments are in good faith, as I did as much as I can to provide trackable sources of what I base my opinion on.