Don't specify a number. Don't specify a partition.
sdX translates to sda, not sda1.
The command should be: sudo grub-install /dev/sda
https://www.gnu.org/software/grub/manual/grub/html_node/Installing-GRUB-using-grub_002dinstall.html
Google says:
https://docs.xubuntu.org/latest/user/C/settings-preferences.html#:~:text=Customizing%20your%20panel%20configuration&text=Moving%20the%20panel%20to%20the,the%20panel%20and%20dragging%20it
Not to answer your question.
Lubuntu is based on the LxQT desktop.
Your formatting seems wrong.
Grub 1 Gb (1024 Mb)
Swap 2 Gb (2048 Mb)
Formatting to gpt? Why have you got 2 gpt partitions. Why not formatted to ext4?
The easiest way is to choose "Use whole disk" (or similar). This will...
Installed it on one of my laptops. (I have several.)
Must admit I found R12, which I updated to Debian 12, seemed better.
I am still tinkering with R13, and it will probably improve.
Don't have a dedicated GPU, just using integral.
I like Wattos. It only uses the Debian Repositories, so it is more of a customization. It has no Repository of its own. Small and very useful.
https://linuxiac.com/wattos-r13-rolls-out-rebased-on-debian-12-bookworm/