Cover up larger holes in the wall

[Måttband92]

Hi! I have moved a doorway and closed up the old one with plasterboard, but there are still fairly large gaps and holes. How do I fix this without it cracking later on?
I also had a funny little "pizza hatch," as we've called it, which I've also closed up in the same way. The wall is made of lightweight concrete with plaster and paint on top.
Should I:
1. Use plaster as much as possible and then fill the rest with putty?
2. Plaster the entire wall?
3. Something else?

Please share any tips and opinions!

 

[tttomten]

Putty and painter's tape

 

[Måttband92]

It won't crack then?

 

[tttomten]

Depends on whether you used studs before you screwed up the gipsin? If done correctly, the tape absorbs the loads.