I see people say this a lot and I have no experience with this but I wonder why you wouldn't use a USB nvme SSD enclosure it seems a lot easier and idk if running it over USB would limit the speed but it could preform better than a USB stick.
A dumb little stick is fine for the occasional "fix something up" or "take a snapshot of a Windows drive because dd is objectively better than anything that Windows itself could do". A live iso distro precludes me from adding a handful of other useful tools.
Late breaking edit : What I ended up doing was formatting a stick as small EFI / 5GB btrfs / rest exfat. Chattr +c the btrfs, and debootstrap in there. Put rEFInd on the efi and tell its conf file about the stick (or maybe it'll detect). Put non-free-firmware & stable-security into apt's sources.list. In a chroot shell, apt get live-task-non-free-firmware-pc gdm3 systemd-timesyncd linux-image-amd64 locales gnome-terminal. Add other tools to suit taste. Fix up the fstab, make /tmp tmpfs, make the exfat mount nofail. With btrfs compression, I can have a gnome environment inside of 2.5GB. It would be even more smol if I could figure out booting directly into Weston.