Tacx App not working correctly

I have now lost my training data multiple times after the Tacx app froze on my Redmi Note 13 Pro (the app became unresponsive). As a result, all data for the respective training session was lost. Contrary to the statement in your FAQ, no intermediate progress could be restored either.
Nevertheless, I am continuing to attempt the Tacx Challenge Cycling Paradise (even though I already had to redo two entire stages).

Today, I completed Stage 5 up to KM 22.3, hoping to continue it after work. Although the app prompted me to "Continue the tour," it was not possible to start the stage from KM 22.3 — only starting from KM 0 was possible. As a result, I rode the entire stage from the beginning again. Despite saving a completed activity with 37.1/37.1 km, the stage still isn't marked as completed; it remains stuck at 22.3 km and shows "Continue the tour." Deleting the previous activity (with 22.3 km) does not resolve the issue.
It is simply unbearable and incomprehensible that I am now losing partial progress for the third time. At the moment, there is no way to continue the challenge.

Has anyone any Ideas?