Hi

For the kind of tough meadow work you're describing with thick fibrous wild grasses and uneven ground, electric mowers generally aren't robust enough for that application. Most of my experience and recommendations focus on conventional lawn care for relatively uniform, maintained grass areas.

The heavy-duty petrol driven machine you're already using is likely the most appropriate tool for such challenging terrain and vegetation. For meadow management with tough stems on uneven ground, petrol-powered brush cutters or specialised meadow mowers are typically the most reliable options.

Sorry I can't help.
Mark