big cracks on the ceiling where the chandlier was for a 5 years

I would advise to smash out plaster around it in order to make sure that the existing plaster is not lose or chipped then bond the area and freshly replaster.

I think the best solution would be to mesh the whole ceiling with render mesh then reskim the ceiling. The render mesh will hold it altogether.

Run sharp knife thru the cra k clear and clean it brush it out glue it with plastering a d fill or plaster depending o depth and leanth large cracks should be plastered but small cracks could be easily repaired and save a fortune

It will need to be removed if it’s cracked as it may have wooden lathe under it and it means the bond between the old horse hair and lime plaster is giving up , so for your own safety it may be best to remove it all and board and skim , you can also board over it if you haven’t got a cornice and skim it

It is better to go to the job site and assess the extent of the damage and then make the right decision.

Carcks normal need filling if haven too many cracks then is better to make replanting