There are too many unknowns to give an answer on this subject.
Well, don't you think this is an important thing to research, then?
There's a list of people who have paid to go into space and spend time on the ISS, something you lot don't even believe exists.
It's not a long list because it is still out of the reach, financially, of "ordinary" people but there are still 7 people who have done it.
So either...
1) They are all lying.
2) They have all been tricked somehow
3) They actually have been to the ISS.
If it's 3 then, from your point of view, this is quite a significant discovery. Even if you still want to cling to a flat earth view somehow it would have to significantly change a lot of your beliefs.
You don't think this is worthy of some research - and yes yes, I know you don't have "funding", nor do I but it took me 5 minutes to find some YouTube video of the one lady on the list and find some footage of her in the ISS and discussing her experience.
This is like C. S. Lewis's quote about Christianity:
"Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important"
You seem remarkably blase about something like space tourism which, if true, could completely shatter your world view.