Visa A Visa B Permanent Residence (PR) and Citizenship

Good day,

I wonder if you can provide me with some clarity on visas, PR and citizenship in Belgium please? Despite online research and a meeting with the commune I still have some questions. We are in the Ixelles commune and their website is not very expansive on these issues, and Covid makes it harder to speak to staff there.

I received a Visa B when I first arrived in Ixelles in Aug 2016, and received other Visa Bs until Feb 2020, when I got a Visa A card. As of Aug 2021 we have been here 5 years. I would like to get Belgian citizenship to permanently emigrate from my country or I still have to pay tax there.

1. Is it true that with a Visa A card I can apply for any job with any employer? Just in Ixelles or nation-wide?
2. Why would my companies lawyer have changed my visa card from B to A? It seems there are advantages to get the B no?
3. Now that we are about to apply for citizenship, we have been told that we have to get permanent residence first. Is this true? Always? With Visa card A? With Visa card B? (I have had experience of govt staff giving different versions before, so I need to check this)
4. Do you know what documents are required for permanent residence at Ixelles?
5. How long after getting permanent residence before I can apply for citizenship? It seems it can be done straightaway. Is this accurate in reality?
6. Do you know what documents are required for citizenship at Ixelles?

I have done online research but have not found detailed and conclusive answers to these questions. Any assistance would be most appreciated.

Thank you.