Transiting Germany with current Corona restrictions

I am an Australian citizen however I hold a German Residence Permit (Type D Visa).

I am currently in the UK and would like to travel to Denmark via Hamburg (Germany).

My journey would look like this: fly from London to Hamburg then immediately take the train from Hamburg to Copenhagen.

I have tried to understand the current corona regulations in Germany but am getting mixed information.

The questions I need to confirm are:

1. Can I enter Germany with just a residence permit (type D visa)?
2. Can I take the train directly to Denmark from Hamburg without quarantining in Germany?

Any help would be hugely appreciated.

Thanks in advance!