I haven't checked lately, but when I gave Bazzite a try around a year ago they had a TON of download options and one of them was a "fully offline" installer, so it was pretty beefy since it had everything they think you could possibly want to install during the initial setup in the iso already. But conversely, I'm pretty sure they had a "minimal" installer that was pretty small, but would need an internet connection during install for anything more than the bare minimum system.