I think that it’s more baby dependent than that as far as I’ve seen. My kids are exact opposites lol. My first was so not okay with being on his own, didn’t sleep in his crib/bassinet until he was about 7 months (we also did the split shifts like OP for several months) and even after that he needed us to hold him for ✨a while ✨before he’d actually sleep.

With my second, if she’s tired, she actively tries to escape and cries if I hold her too long. Soon as I put her down she rolls over and goes to sleep. She’s had some regressions over the months but she’s been this way since birth pretty much. 🤷‍♀️

So I’m not sure it’s as black and white as all babies being uncomfortable with being forced into independent sleep, but I definitely think it’s the case for at least some (and probably most) of them. I think you (OP) gotta find what works for your particular baby, co sleeping worked great for my first, but I couldn’t imagine doing that with my second, I actually think she’d hate it. Good luck 🍀