The biggest difference I've seen is around product maturity. At a startup you typically have something very new and no reputation. You have to move very quickly to build it out and expand, and you sacrifice a lot to make this happen.
At a big company you're typically working on something much more mature, making lots of money, with many users who rely on it. You still need to make it better, but it's now much more important not to break what's already working. Even if your project is a new one, you still have the company's reputation to protect so you don't hurt existing products. Different companies handle this different ways (I lean towards investing in efficient end-to-end testing and experimentation) but all the options here trade velocity for reliability.
At a big company you're typically working on something much more mature, making lots of money, with many users who rely on it. You still need to make it better, but it's now much more important not to break what's already working. Even if your project is a new one, you still have the company's reputation to protect so you don't hurt existing products. Different companies handle this different ways (I lean towards investing in efficient end-to-end testing and experimentation) but all the options here trade velocity for reliability.