Check out the specific one I mentioned. It's 5" in diameter, so much bigger than the typical sink plunger, and it works well with large bell trumpets. Cutting the hole is trickier than the generic red plunger, but not a big deal. It's the one I recommend to students on a budget. (But the KR is much better!)

Edit: this one: https://www.amazon.com/dp/B07Y837NZN/ref=cm_sw_r_apan_glt_i_R0CRFD4AK41DNNWJXF5N