I used upfiring for a number of years. They work fine. You have to adjust them correctly for your room , meaning angles, whether you point them away from you or toward you, affects how they sound. Meaning, you can have the angle facing toward you, which will reflect off the ceiling directly at you, OR you can point them toward the wall and bounce them off the wall and ceiling. You don't get ideal placement of sound in every case, more spaciousness for sure. Discrete sounds still work, especially "around the room" sound. You also have to calibrate them carefully, so it can take time. If you only do 2, it doesn't really work. You need 4 at least. I would not say scrap the idea off-hand, but this method takes a lot more time to get working.
My new room has a ~30ft cathedral ceiling, so I am going to have to go all on-wall here for surround and atmos. Currently I am 2.1 for now. We just moved here knowing it was temporary. I am looking for a place that will support my system, and the one we looked at last weekend has a nice sized room that will support overhead atmos.