If the water level tools and other methods showed a consistent distance above the horizon, it would be undeniable.
It's things like this which make me struggle to believe you are sincere in what you say you believe.
You yourself have posted videos which show the horizon rising and falling over the course of a day.
So you do understand that there are atmospheric effects which can change the observable horizon, now you are demanding consistent results and claiming that if that can't be achieved then it discredits all these experiments.
The consistent thing which all these experiments demonstrate - and multiple methods have been shown on here since I've been posting here - are the two results that:
1) Horizon dips below eye level and
2) The amount of dip increases with altitude.
This is as predicted by the globe earth model. Whether the degree of dip is exactly as predicted by a mathematical model is not relevant. For a start most of the experiments have merely sought to show the two results above, they haven't measured exact angles of dip. And secondly because of the above atmospheric effects - the ones you yourself have cited in the past - the exact mathematical model and reality may not perfectly match. But the two results above are still good enough to give confidence of the globe earth model unless there is some way of explaining those results on your flat earth model.
The experiments I've read about from Rowbotham are the one on Brighton pier and one in the Grand Hotel in Brighton. Neither of these structures are tall enough to observe a measurable horizon dip. In the link you posted above he goes on to claim that the same result was achieved from other higher vantage points but there are no details, no evidence he actually did the experiments, it's just him saying it. Here you're being shown photos and video of other experiments which show a very different results and all you've done is wriggle and try and discredit anything which doesn't back up Rowbotham's claims. And all the while you have refused to do any tests of your own.
The silly thing about all this is that the horizon could not rise to eye level on a flat earth anyway. If we agree that the horizon is a point on the earth which is the limit of your vision then it would still be below eye level on a flat earth because it's a triangle between your eye, the ground directly below your eye and the point on the horizon:
I've seen you grumble on here about "appeals to authority" but this is all you're doing here - your authority is Rowbotham and so anything done which contradicts his findings is dismissed somehow. If you dispute the findings of all these experiments then perform your own tests and post the results for review.