on this video you can see that I start a new translation with 0 ongoing translations.
Then 2 things happen:
It seems that there are two issues showing here:
One issue is about restarting a translation that was previously published which is showing the previous translation when it should start from scratch. That is captured in: T192065: Starting a new translation is loading contents from a previously deleted one. The current ticket seems a duplicate of that one. So unless it is a different case in some way, I think it can be closed as a duplicate.
The other issue about the option to restart being missing was unexpected. This was part of the original spec in T168287 and it was not implemented. In the more recent follow-up ticket (T220790) it was also mentioned in the spec:
We need to make sure that, as the warning promises, the user can restart the translation to use the newer version (knowing that this implies discarding all the work done so far).
However, it seems not to be finally present. I created a specific ticket about the option to restart: T228968: Provide an option to restart the translation when the source article has changed too much