[{_id:"Organsiation 1",district:[{_id:"District 1",property:[{_id:"Property 1",address_line_1:"Adress 1",installation:[{_id:"HS01",installation_type:"Gas boiler",component:[{_id:"P01",component_type:"Circulation pump",},{_id:"EXP01",component_type:"Expansion tank",},],},{_id:"HW01",installation_type:"Electric water heater",component:[{_id:"P01",component_type:"Circulation pump",},],},{_id:"V01",installation_type:"Ventilation",}]},]},{_id:"District 2",property:[{_id:"Property 2",address_line_1:"Adress 2",installation:[{_id:"HS01",installation_type:"Geo Heat Pump",},{_id:"HS02",installation_type:"Gas boiler",}]},{_id:"Property 3",installation:[{_id:"HS01",installation_type:"Gas boiler",}]},],}]},{_id:"Organsiation 2",district:[{_id:"District 3",property:[{_id:"Property 1",address_line_1:"Adress 1",installation:[{_id:"HS01",installation_type:"Gas boiler1",component:[{_id:"P01",component_type:"Circulation pump",},{_id:"EXP01",component_type:"Expansion tank",},],},{_id:"HW01",installation_type:"Electric water heater",component:[{_id:"P01",component_type:"Circulation pump",},],},{_id:"V01",installation_type:"Ventilation",}]},]},{_id:"District 4",property:[{_id:"Property 2",address_line_1:"Adress 2",installation:[{_id:"HS01",installation_type:"Geo Heat Pump",},{_id:"HS02",installation_type:"Gas boiler1",}]},{_id:"Property 3",installation:[{_id:"HS01",installation_type:"Gas boiler1",}]},],}]}]

db.collection.aggregate([{$match:{"district.property.installation.installation_type":"Gas boiler"}},{$addFields:{district:{$map:{input:"$district",as:"d",in:{$mergeObjects:["$$d",{property:{$map:{input:"$$d.property",as:"p",in:{$mergeObjects:["$$p",{installation:{$filter:{input:"$$p.installation",cond:{$eq:["$$this.installation_type","Gas boiler"]}}}}]}}}}]}}}}}])