vocal mic for opera singers

Last Christmas I recorded a grand piano+ mezzo soprano+soprano. I used a ldc mic (Austrian audio 818) and a zoom f6 32bit float. Unfortunately it sounded bad. There was a nasty distortion in the higher frequencies at some moments both the vocals came in. The mic did not clip and was put about 3m from the vocals. In fact the on camera mic (sdc stereo mic) was ok and saved the day.

Has anyone here ever recorded opera singers and can recommend:
a good mic $1500-2500 range and a pre at same range

Harmonics in the opera voice is a fundamental characteristic to the sound and I wouldn`t want these overtones to be compressed. Any specific mic used as a preference. Any ideas?

Thanks in advance,
Remigio