Opinions!!

Could try OB’s. PureAudioProject Quintets, Trios, Jump in at any size. Upgradable without loss of investment, efficient, Just ask VPI, Whammerdyne, and more that use them to demo their own products. Says a lot. Once heard, not easily forgotten. 

@bbenzaquen6343- I’ve found both Kimber Selects (KS-1130 & 1030) and Synergistic Research (Tesla Apex & Analogue Tricon), to pass whatever determines accurate ambience retrieval, without hindrance.      I’ve no doubt; their later iterations would be even better, in some ways.

I too used the ML Prodigy. They sound better bi-amped with an active crossover. Better yet are the Quad 2905’s. I have owned two pairs of 2905’s and one pair of 2805’s for ten years or more, and am just experiencing my first failures. One panel has gone (out of 32) and one high voltage transformer.

If you don’t use them like sonic bludgeons they seem to work fine - at least, mine do. Once you’ve lived with ESL’s, I don’t think there is any going back. One highly respected member here owns MBL’s and he opined that they were better than anything but ESL’s.

If you like the ESL sound, stay with it, I say.

@b_limo  had an interesting suggestion. FWIW, this interview with MBL might add to your understanding of their approach: https://parttimeaudiophile.com/2020/08/06/a-deep-dive-in-the-high-end-sitting-down-with-mbl/

I agree with Rodman99999 - stick with electrostatics / planer speakers- I compared my Maggie 1.7i to Martin Logan and stuck with my Maggies- better sound stage. I do not know your price range - but the Maggie 1.7i are only $2,200 new. The Maggie 3.7i are $6,500 new. Everyone complains about the base lacking below 50 hertz with Maggies - solution - add The Swarm (4 subwoofer array and the system comes with it's own Amp) - got a TAS Golden Ear award twice - cost $3,200.  This set up is worth investigating - especially in your large room.  

Just my two cents - Happy Listening