>>106477713
>I make /boot and /boot/efi [...] separate
They're 2 separate things with separate purposes:
>/boot/efi
This is the EFI system partition (ESP). It can be mounted at /boot/efi or /efi, it doesn't really matter (but you have to tell your bootloader where it is; systemd-boot will figure out by itself but GRUB i'm not sure).
It's required by all (U)EFI platforms so they can boot, and contains the actual bootloader at /EFI/BOOT/BOOTX64.efi (or BOOTAA64.efi for arm64, BOOTIA32.efi for x86, BOOTRV64.efi for RISC-V etc).
>/boot
This is what's called the XBOOTLDR partition. It's completely optional -- The main reason why it exists is because, if you first install Windows, your ESP might be too small to fit the kernel + initramfs (or multiple copies of them if you have multiple generations). So they made a separate partition just to store those.
If you don't dual boot and installed Linux with a clean format then you probably don't need it. When formatting my drive I use 512 MiB for the ESP so it has plenty of room for many generations of NixOS kernels+initramfs'es.
TLDR is if the only subdirectory of /boot is /boot/efi then you don't need a /boot partition. But if you choose to delete it make sure to not fuck up and accidentally delete /boot/efi, because that you do need, and deleting that will brick your system.