I do a lot of bird photography, which usually means slightly higher ISOs to get fast shutter speeds for those fast little guys, and am currently using a Z5 with a Sigma 150-600mm C + FTZII. I currently do a lot of manual focusing since the auto-focus is a bit slow and not so great at picking out the bird from the trees. I still get some great photos, but I find myself wanting a bit more.
I want to eventually upgrade to the 180-600Z and I'm leaning towards the Z6II at this point (though the Z8 is also tempting), but I wanted to get some thoughts on what I should upgrade first - the glass or the body? Next month I'll likely be able to get one or the other, so I was looking for some guidance o