Well, we probably can't ever know exactly how we got here, (just guess) so I guess you can believr whatever you want about that, but we do know that the earth is a globe, so the fact that it is compatible with flat Earth doesn't mean anything.
We can't know anything for certain, at best, all we have in life are probabilities.
What's more likely, earthlings coming from non-life, something spectacularly unlikely if not impossible, or earthlings coming from other planets, they themselves coming from other planets and so on?
The former is one out of a trillion trillions if not impossible, admittedly by Scientists, yet many if not most of them believe it (because it's like a religion with these people, they have to believe higher orders of being, such as life, evolved from lower orders of being, such as non-life, which itself came from even lower orders of being (chaos, non-being), the latter is, I'm not sure exactly, a 50/50?
While Nasa claims to have not found any life in outer space, nothing they say can be verified, so who cares?
They are a government agency.
Scientists have found extremophiles capable of withstanding some of the harshest conditions on earth, high levels of hot, cold and radiation, not unlike the conditions found in outer space, but then perhaps we can't even be sure about that either (shrugs).
So life probably has no origin.
Matter, energy, space and time probably have no origin either for the same reasons.
Now while even if panspermia is correct, or most probable, that doesn't prove flat earth, and I'm not a flat earther, but it does make flat earth more attractive on some level, because it's more compatible with panspermia, and if flat earth is just as likely to be true as round earth, give or take, but life would have an even easier time spreading itself throughout the cosmos on an infinite, immortal plane, then perhaps that makes flat earth more probable than round earth, in a sense.