Can you post even one brand that is listed for both LFMC and LFNC?
No, which is why I changed what I originally said.
I can't find one that is listed for both metallic and non metallic conduit, but Arlington's "Snap2IT" zinc connectors are a metal connector listed for non metallic flex, but not listed for metal flex - which may be a little surprising to some people.
I use LFNC often to connect irrigation well pump motors (usually in the 50-100HP range). I prefer non metallic flex because condensation buildup in the flex seems to rust out the metallic flex - and it is fairly unavoidable. I have also seen many broken non metallic connectors where used in this application. Broken conduit fitting in this application means a mouse nest will likely be in the motor, will usually also mean they will degrade winding insulation and motor will need rewound. Not listed - I understand, sometimes you have to do what works best, and hope inspectors will understand when you explain it to them. Most of the inspectors I deal with have done this before and understand the problem very well as they have gone through it themselves.