I wonder if this tournament does not have a negative impact and if it would not be better to stop it, in the interest of the development of Go in Europe.
Let me explain:

In Europe, a radically different choice has been made to insist on sportsmanship.

It is in the rules of our Federation, and this allows us to handle cases where the rules are insufficient or the lack of resources of the organization is felt.

A real example:
- Player A forgets if it is his turn to take the last ko or if he has to play a threat.
- Player A asks his opponent B, who does not answer
-Player A resumes the ko, B calls the referee for a forbidden move.
Thanks to the rule of sportsmanship, the referee decides to cancel the forbidden move and continue the game.
We see that this is not at all the logic of the transatlantic tournament, where the player A should have paid more attention to the last move / ask a referee before playing, etc.
For me this change of logic poses several problems:

The first and the least important, but that we can already see is that this implies a very good organization, which is not compatible with the lack of current means: We already see that in this topic: people complain now about the time schedule, which was not the case before(and its logic, if the most important is not what happens on the board,but to decide a winner no matter what, you have to put more attention to this). I'm not even sure that this level of requirement is achievable by an online tournament.

The second point is that these professional players represent us and influence us. So to see them in a tournament where they can not rely on sportsmanship, it's a long-term risk to influence the behavior of go players in Europe, a behavior's change that I do not see as positive, and which could therefore harm the development of Go in Europe

I think this is utter nonsense.
Matches like this are good for European and American Go, but they wont affect the average amateur player and how they play at all

The second point is that these professional players represent us and influence us. So to see them in a tournament where they can not rely on sportsmanship, it's a long-term risk to influence the behavior of go players in Europe

Can anyone explain why 152 in the last game requires White to come back and defend at O5?

I am surprised I don't hear much about white 128 - when white decided to capture at M8 (ponnuki) instead of capturing two stones in the upper right when black peeped. Stephanie approved of that during the game comment, but I thought it's better to capture two stones, and LZ seems to agree: it gives 90+% for capture two stones, vs 50+% for the ponnuki played in the game.

I've got an idea why Ryan ignored n13 and went for the trade: if he answers then black has in sente created the option for his group to live unconditionally at k13 so doesn't need to worry so much about being closed at k9 (he just answers to live in gote) or white taking the inside eyes forcing him to run out. That's clearly a gain for black compared to if white had peeped at n12 earlier (say instead of m9). So this simple logic shows that white would have an inferior position to if he could undo and play better in the past. So he goes for a drastically different result which cannot be argued with simple comparison to be slightly inferior because it requires much more judgement, but it ends up being hugely inferior. I often make this mistake myself too, particularly when fighting spirit gets the better of me.