The challenge with the LRS+ is that it is not just a 4 Ohm nominal speaker, but it does not really ever go above 4 Ohm, and it dips to less than 3 Ohm in the midrange. You’re using high power amps, but what you should really try are high voltage amps, mainly Class A tube or solid state.
I am a Margules dealer and suggest that you look at the I-240 integrated. They would be an excellent match for those speakers in the room size you state, as long as you’re not rocking at stadium levels, which the LRS+ likely cannot do anyway. I don’t recommend that amp very often, but I’m certain they will pair incredibly well. They are 25wpc of pure Class A with a proprietary servo circuit design that is a great combination of muscularity and finesse. Especially with aftermarket tubes like the Psvane EL34PH and Radiotechnique 6189, they can make hard to drive speakers rise and shine in medium sized rooms.