Hello Rolf... and WELCOME to LMF...
Wow you are looking at a LOT of lawn...
Your 3 Hectare area is about 7.5 Acres... You are going to be hard pressed to find any mower in the residential home owner class that will keep up with that type of extreme duty... I'm thinking you are going to have to go to a bit larger machine OR cut back on your acreage that you want to keep tidy & well groomed...
To regularly mow my 10 + acres I use a 6 foot ZTR and/or a 7 foot rear mounted finish mower... Using anything smaller will only require too many hours, and just ware you and the machine out....
:smile:KennyV