I think it should be fairly easy to scale up the force of any automated wire cutter design enough to cut filament. There are a lot of DIY ones on YouTube with various designs.
You could also consider using a hot knife cutter, which would require very little force. I suspect that would leave a burr on the cut ends, which might be problematic somewhere down the feed train. Not knowing barely anything about 3D printers or your application I can't say whether that's a concern. You can get commercial hot knife cutters made for cutting rope or nylon webbing or make your own. A cheap soldering iron with a razor blade tip would work well for a DIY hot knife cutter or perhaps just a piece of nichrome wire.