Bootloader installation failure

hello,

The first time I installed Endeavour OS, I made a separate partition for it to install the boot loader in . However, I read that its a bad idea to have multiple ESP on the same drive. So I tried to re-install the system and by default, I found that it will install the bootloader in the same windows efi boot partition. So, I left it as it is but at the end of the installation, it always gives an error saying installing the bootloader failed.
Are there any configuration/settings needed so the OS is able to write into the windows EFI partition?
And by the way, I did not choose grub as the bootloader type. I chose the system default boot

In all cases we need the installer log to see what actually exactly was failing.
read here: how-to-include-systemlogs-in-your-post

From my experience, it is never a good idea to reuse the ESP from an installed Windows OS, even using the same drive to install Linux in a dualboot scenario is not something i can recommend fully …

It is true that it says there should be only one ESP in a system. I run a system with 7 drives each one with its own ESP no problem with that.

And in addition in most cases the ESP from already preinstalled Windows is to small to add EndeavourOS Bootloader files to it we have a minimum of 1GB for systemd-boot and around 300MB for grub.

In your case it can be you have fastboot enabled on windows this should be set of (search windows forums for how to do that)
Or the Windows ESP is in unclean state.
You can try resolving this 2 issues from windows and try again to reuse the ESP if it is in correct size. If not, go to create a new ESP in case of systemd-boot min. 1024MB flagged as boot and set mountpoint as /efi (fat32). Read here also:
live-iso-tricks-tips