Just my thoughts, but for me the Z8 depends on what I’m using it for and what lens I have attached. If I’m using the camera for holiday and city break types photography, then yes I’d agree it’s a litter bigger and larger than I’d like, as typically I’d want to be as small and light as possible.
However if I’m doing wildlife or birds and am using bigger lenses like my 180-600, 400 f4.5, 100-400 or 500PF, then to be honest, an extra couple of hundred grams in weight is hardy noticeable over something like a Z6 or Z7 II, and the extra size of the Z8 gives a much better handling experience with larger lenses without having to resort to a battery grip.