The top-end rolloff is a feature, not a detractor for the 57 and other dynamic mics. If an engineer wants a mic that extends up to 20kHz, they will simply grab a condenser mic. On guitar cabs for instance, you really don't want more of any of the frequencies above the 57's rolloff, unless you...
Sell the sm7b+cloud lifter combo. too much money for yucky results. Get a Blue Encore100 it has very nice ambient rejection and nice sound. It works 10/10. Unlike the sm7b.
Thank you for the explanation! I'll research more into this mic for sure! I'm gonna try to work out the SM7b but this is on my radar to try next when I can.