You’ll probably notice very little difference, especially if you go with one of the default partition layouts. If you were to manually lay it out, you’d need to make sure you have an EFI partition on a GPT partition table, but otherwise it should be normal.
Like others have said, Secure Boot can be miserable, but in my experience, it works automagically with Debian so long as you stick to official kernel packages. The only hiccup I’ve had before (assuming a normal kernel package) is that on my shiny new Thinkpad E16, I had to go into the UEFI settings and enable non-Microsoft certificates (it was a single toggle). After that, my experience with Debian was pretty smooth (I had a minor issue with Wi-Fi, but it’s not relevant to your question).
Nothing. Nick Locarno basically did that, and it ended TREMENDOUSLY WELL. 😉
Granted it was only one ship; the rest were mutinies.