I removed your responses and futher clarified why your disproof did not succeed by FE rules. The basic idea is to come up with an explanation for everything, however implausible. Confronting this with RE/regular world expectations made me angry, possibly you if you got blindsided by it. Dorothy, you're not in Kansas any more.
If you think you can patiently educate and lead them through steps to "the world must be round", I and many others have tried. They. Will. Not. Do. That. In fact, they usually don't answer RE posts like yours. They already did, it's in the wiki, etc. If you find the explanation in the wiki flawed, explanations of that: it's not done, it's just one model (some other model may work), it needs work. Generally they seem impatient about convincing you, they want to spend their time explaining to the credulous. or chatting among themselves to develop more FE models. Often, after some brief explanation that you will find unsatisfying, and referal to the wiki, they become exasperated and say they explained it already and leave in a huff.
Here are mine that don't get answered: sextant/latitude/north star, equatorial mount, amsat (amateur radio ioperators build their own repreater satellites and get them launched, multiple proof points), doppler red shift from stars, spacex, maps, amateur radio (multiple proof points, satellites, beam antenna aiming angles, moonbounce), etc etc etc. And good luck getting them to explain how equatorial mount and north star/latitude/sextants work on FE or RE. I had one who was skeptical that the north star angle always equals latitude.
The key thing that most REs find ludicrous is the space conspiracy - all countries space agencies, all astronauts, maybe all astronmers (no way to tell how many are phds cynical liars and how many have been successfully brainwahsed or intimidated. You do have to admit that an astronomer saying the earth is flat may have career consequences.
Here's a fun one: the sun on FE, while actually always above us, seems to be on the horizon vecause of vaniching point and perspective. Good luck explaining what those really mean, but once they knew the phrase "vanishing point", just gotta use that to explain where the sun goes at night, it vanishes!
There are many models, so it could be several things
There might be a flat earth model you don't know about that could explain your observations. You can't prove there is no FE model that explains it. Bear in mind that FE models can have changes to the laws of physics or as yet unobserved features that do things like make comets appear to be somewhere other than they are. A quick example, perhaps silly even for FE, but suppose the dome had a bunch of "wormholes", where things like comets go into the dome and pop out somewhere else after a delay. Since that could all be, you haven't disproved FE.
Their calculations might be wrong
They might have wrongly measured the distance or done the math wrong. There could be a particularly difficult calculation that people are prone to make the exact same error and they all made it. So again, if there is a way to imagine an explanation, you have not disproved FE.
How do you know the people in other parts of the world weren't lying
According to FEs, there is huge money and power in knowing FE but fooling everyone else. Explanations of this are generally vague. Almost all FEs believe NASA is a giant conspiracy created to fool us and kill leakers. It is FE easy to say there could be a conspiracy to hide all things RE, Perhaps NASA knew about the experiment and sent thugs to bribe/threaten them to lie that RE is true. Again, there is a possible way your proof is invalid, so FE lives.
Maybe degrees have a different length in different parts of the world but they measured wrong
You have no way of knowing how long a degree is. You haven't been everywhere. You can't be sure your measuring tool worked, or even that it doesn't work differently. I recently read an FE post that said the only way to know the size of the moon is to go there with a ruler.
Were you there? The entire story could be made up, all the numbers could be lies
85%, that's not 100%. You need 100% for proof.
There are many ways this could be wrong, so one can still believe FE with so much possibility of dismissal of your idea.
Really?! Can you please explain why?
Because they have seen many many many FE videos, each showing them a problem with RE. And I think for various reasons they want FE to be true, mostly 3:
1. they get pleasure from conspiracy
2. they don't want to feel like they are living on a rock spinning wildly every which way, an accident of evolution in some obscure corner of a vast mess. They want to be in a simple place at the center of everything befitting their central place in existence
3. they think the Bible says the earth is flat
Given they have holes in RE, reason to like FE, and you can't prove the earth is flat, carry on with chatting with other FEs in endless speculation of how the world is flat.
And by the way, understand, FE doesn't mean flat necessarily, there are toroid and inverted and dished and bulged, all trying to solve the probems with flat. They have multiple models, you know, if one is wrong, another might be right. FE means not round. The only shape, for whatever reason. they reject. I think thast is more about rejecting the consensus rather than the shape.
I hope I saved you time and aggravation. The challenge of disproving FE is little or nothing outside the FE world. Inside FE, it is impossible to disprove FE on their terms, and they set the terms.