Some would argue, and do argue, that deads aren't a back exercise at all, that it's just an isometric hold for the back and the prime movers are hams and glutes. I think it's more complicated than that though. You don't need "full" range of motion to cause a hypertrophic response.
Read the caption here. I wouldn't argue with that.
https://www.instagram.com/reel/C3Nc7tkilyP/?igsh=a3k4cmlzbWZxMjQ5As far as doing a back routine of chins and deads, I think you can go really far with just that. I would do deads first, based on my experience that low rep deads do not lower your strength for chins or pulldowns, if anything it might make your chins stronger in the same workout. Something about neuromuscular potentiation. You could test this theory like this: do a few heavy singles on deads then test your forearm strength on grippers. Next workout do some grippers first and see if you notice a difference. Anyway, doing chins first would conversely reduce my deadlift numbers. That's my experience, you might be different, can't be sure.
I would advice against trying to consciously contract and lengthen and shorten the lats on deads. I remember seeing some pros like Flex Wheeler doing deads on smith machine and pulling the shoulder blades back at the end of the movement, a sort of a semishrugging movement. I think it might be injurious due to the high load, might even pull or tear the lats (happened to me several times).
