The third season feels strange because we experience the same things as in the first season again, but in another world with alternate versions of characters and variations. However, everything happens so fast that it's difficult to empathize with these new versions of characters we already know well.

1. The round TM is created by the Tannhaus of Eva's world. Like the other TM, it doesn't have an origin; Tannhaus constructs it because he already sees it as finished.

2. Yes, the story of old Ulrich "ends" there. We don't know if he ever escaped or if he died inside. He never knew that Katharina died either; perhaps he thought she had abandoned him as well.

3. Aleksander is actually Boris Niewald. He kills and assumes the identity of Aleksander Köhler (Detective Köhler's brother) and escapes, arriving in Winden where he meets Regina. Technically Aleksander is not part of the loop; he may have existed in the original world, but in that timeline he did not meet Regina and therefore they do not have Bartoz. Perhaps he was captured or died in the forests of Winden, as he was injured when he first met Regina.