Syntax errors are detected in generated GRUB config file

I was trying to update grub config via Grub customizer, and it failed, and when I run update-grub2 I get this error output of update-grub2:

ks@ks-pc:~$ sudo update-grub2
[sudo] password for ks: 
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.2.0-25-generic
Found initrd image: /boot/initrd.img-6.2.0-25-generic
Found linux image: /boot/vmlinuz-6.2.0-24-generic
Found initrd image: /boot/initrd.img-6.2.0-24-generic
Found linux image: /boot/vmlinuz-5.15.0-76-generic
Found initrd image: /boot/initrd.img-5.15.0-76-generic
Found linux image: /boot/vmlinuz-6.2.0-25-generic
Found initrd image: /boot/initrd.img-6.2.0-25-generic
Found linux image: /boot/vmlinuz-6.2.0-24-generic
Found initrd image: /boot/initrd.img-6.2.0-24-generic
Found linux image: /boot/vmlinuz-5.15.0-76-generic
Found initrd image: /boot/initrd.img-5.15.0-76-generic
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Found linux image: /boot/vmlinuz-6.2.0-25-generic
Found initrd image: /boot/initrd.img-6.2.0-25-generic
Found linux image: /boot/vmlinuz-6.2.0-24-generic
Found initrd image: /boot/initrd.img-6.2.0-24-generic
Found linux image: /boot/vmlinuz-5.15.0-76-generic
Found initrd image: /boot/initrd.img-5.15.0-76-generic
Memtest86+ needs a 16-bit boot, that is not available on EFI, exiting
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
error: out of memory.
error: syntax error.
error: Incorrect command.
error: syntax error.
Syntax error at line 702
Syntax errors are detected in generated GRUB config file.
Ensure that there are no errors in /etc/default/grub
and /etc/grub.d/* files or please file a bug report with
/boot/grub/grub.cfg.new file attached.

/boot/grub/grub.cfg.new: https://pastebin.com/VpaF4Epa