Try reinstalling Ubuntu, following this guide
Previously back up the files on your /dev/sda1 partition
The Efi System partition must be at the beginning of the disk, /dev/sda1
Disable secure boot and fast boot in setup.
Start a live session of Ubuntu.
Once the boot is complete, open a terminal and run:
sudo apt update
sudo apt install gparted
sudo gparted
From gparted, select the HDD drive.
Unmount it if it is mounted.
Create a new gpt partition table. WARNING: this will delete the existing data on the device.
In the free space, create a 1 giga partition, Efi-System (Fat32).
Next, create a 80-gigabyte partition, ext4 system.
Create another 8-gigabyte partition, swap system.
Create another remaining partition that you plan to use for Linux, ext4 system.
Apply the changes.
Close gparted.
Close the terminal.
Start the installation.
Choose manual partitioning
Grub, by default, on the SDD drive, Efi System Fat 32.
And select
The 80-gigabyte partition for /.
The 8-gigabyte partition for swap.
The remaining one for /home.
Continue with the installation.
The sizes and number of partitions are suggested based on my experience and preference for having a separate swap and /home partition to preserve personal files during future updates.
In particular, I remove the Firefox, Thunderbird, and Libreoffice applications installed as snaps after the installation is complete and install them from their PPAs or directly from the original packages from their developers.