Uhm the Yamaha is stable down to 2 Ohms. So no, you're not suffering and your Yamaha is doing tremendously. Delivering 140W into 8 Ohms, 230W into 4 Ohm and 340W into 2 Ohm at 1% Max THD
Review - https://www.audiosciencereview.com/forum/index.php?threads/yamaha-a-s701-stereo-amplifier-review.55211/