Nobody's saying they lie about everything. But they do tell lies, right?
You admit that.
So tell me how you sift through the truth and lies to be sure?
You seem to be acting like they lie about everything.
I would judge it based upon several factors:
Does the claim make sense?
Does it match with observations/evidence, especially my own observations?
Do they have a reason to lie about it?
With some, it is quite clear that they are likely lying, to try to line their own pockets, and it doesn't make sense.
And scientists are more likely to make mistakes than outright lie.
For the shape of Earth, it does make sense, no matter how much you want to claim it doesn't. The only reason you claim it doesn't is because you have already rejected the RE and want to pretend that rejection is justified. You cannot demonstrate any part which doesn't actually make sense. And by that I also mean having the alternative make more sense.
It also matches with loads and loads of observations. Again, you cannot provide a single example of where it doesn't match. You can blatantly lie and pretend it doesn't match, but you then flee from that lie rather than even attempting to justify it, fleeing from trivial questions which show your claims are wrong.
And most importantly, there is no reason to lie about it. There is nothing to be gained by pretending Earth is round if it was actually flat.
So with all that, there is no reason to think the RE is a lie.