I wondered are kemper owners convinced the high end is as clear & bright as a real amp?
Only I'm not sure I'm finding so. Maybe my budget speakers.
In a word? Yes.
Better still, my Kemper with the appropriate profiles sounds the way I want and expect. Even though I can require tones to fit a large range of musical textures and thus a range of amps tones which are vastly or subtly different, the KPA is more than right on the money compared to the "real amps" I have used for live performance or recording.
In your situation, fortunately, the question of you speakers being a "problem" is not difficult to rule out, IMO. As an example, toting a KPA to a well stocked music/audio store is much easier than finding the right mic for use as an overhead...
The KPA has no ugly reproduction characteristics which I have run into. If the amps to be profiled are good enough to produce what I want to hear, the KPA is superb in capturing what I'd be able to get with just the amp'cab and the same mic placed where it's placed.
Far closer than any other method I can think of.
Can it be profiled differently, miced differently, amp dialed differently, played through a different speaker, DI, etc., etc., and get "different results? Yes... without a doubt. The differences can be or seem large or nuanced... Without regard, any difference can rule a result unacceptable.
Maybe some recorded examples of what isn't sounding right to you would allow some informed opinion.