Thank you for reaching out to the Wefugees Community.
On your first question, please have a look at this thread in which we discussed the 6-months period relevant for “Dublin cases” in Corona times already.
Regarding your two other questions, it will be helpful if you could specify a bit more. Generally speaking, “changing” the Duldung is only possible if you applied for a residence permit, you meet the respective requirements and the immigration office is deciding positively on your application.
Please don’t hesitate to get back to us with any further questions or if you want to discuss your situation in more detail.
All the best,