Travel within the Schengen area with Fiktionbescheinigung

I have a Namibian passport and I'm currently working in Germany with a National long-stay D visa which will expire early May. My appointment at the Auslanderbehorde for the residence permit card is on the 29th of March.

I want to travel to Italy in mid-May, by then my visa will be expired. I know I will get a Fiktionbescheinigung at the Auslanderbehorde, but I'm not sure which type. As a Namibian, I would usually need a Schengen visa to travel to EU countries, but I know my D visa entitles me to travel within the Schengen area, so will this be possible when I only have the Fiktionbescheinigung?

I'm pretty sure my permit card will not be ready by my intended travel date considering the pandemic and Ukrainian refugee crisis which I've heard is placing a bit of strain on the Auslanderbehorde in Leipzig.

EDIT: Whether or not I can travel seems to depend on whether I get my Fiktionbeschenigung based on paragraph 3 or 4 of Section 81. My interpretation is that I will get it based on (4):

(4) If a foreigner applies for an extension of his or her residence title or for a different residence title before his or her current residence title expires, the current residence title is deemed to remain in force from the time it expires until the time of the decision by the foreigners authority. This does not apply to visas issued in accordance with section 6 (1).

Because I am indeed a foreigner applying for a different residence title before my current (national long-stay D visa) residence title expires. Nowe we can arque about what "residence title" means and whether my D visa qualifies as one which seems to be the point of contention here, since everyone seems to believe that my residence permit application counts as a "first time" application. According to this document issued by BAMF:

The five types of residence titles are as follows: a visa, a residence permit, a settlement permit, an EU long-term residence permit and an EU Blue Card

Therefore, though I am a first time applicant for a residence permit, I am not a first_time applicant for a residence title. My conviction on this matter is further bolstered by the fact that later in paragraph for they go out of their way to specify that:

This does not apply to visas issued in accordance with section 6 (1)

Section 6 (1) being for Schengen visas and transit visas. My visa being of course based on paragraph (3) of Section 6, not the exception (1), you could see why I would think this does apply to me.

So, can anyone tell me where my logic goes wrong? None of the information that is valid for a US citizen is valid for me so I cannot refer to those previous posts and existing questions as I simply do not think they are relevant to my case, as no US citizen had to go through the D visa application.