My current export is reaching the php timeout. Right now, the number of record is about 60K, and will keep increasing so my plan is not to increase the timeout forever but look into providing my client the possibility to export his data by chunk of records. So I look into the ExportModel and ImportExportController class, but didnt find a way to extend the database request.

any experience on this matter please ?

so idiot i am, it was right in front of my noise. basically you can do it directly in the exportData() method provided by the ExportModel class it will look something like this in my case

 $result = self::make()
                ->with([
                    'project_type'
                ])
                ->skip(10)
                ->take(5)
                ->get()
                ->toArray();