boot – Upgrade System Firmware with no EFI space after relocating most I can do

My /boot/efi does not have sufficient space. Even after temporarily relocating /boot/Nicrosoft to /home, Upgrade System Firmware required 71,4 MB, but only got 69,7 MB.

> $ df -h /boot/efi 
> File system     Dim. Usati Dispon. Uso% Montato su
> /dev/nvme0n1p1   96M   30M     67M  31% /boot/efi

There is this boot/efi/EFI/Dell/bios/recovery folder that has a couple files such as BIOS_CUR.rcv (about 20 Mb each) which, I guess, are needed for recovery and can perhaps be temporarily moved elsewhere?

EDIT: the system is already dual-boot since a year. Modifying the EFI partition has the obvious risks that system can break up and I will not do that. My version is Ubuntu 24.04.4 LTS. I don’t see how this question can be similar to the one that is titled How much room is required in the EFI System Partition (ESP) before installing a partitioned Ubuntu to dual-boot with Windows?

As for my device specific part of the question, machine is a Dell Inc. Precision 5490.