Please clarify why.
With a DSLR, you don't require the sensor to view the scene. For example you can shoot a slow kit lens, and OVF image clarity won't be affected. Same goes for studio work if you're shooting at f/8 or smaller, mirrorless offers no advantages in those situations. In fact I prefer flash photography with my DSLRs and not so much with my A7III. On the flip side, I do prefer mirrorless when I'm shooting fast primes, because OSPDAF is much more precise in scenarios that require shooting wide open. Hence I like both type of cameras for different scenarios.