Touchpad on my laptop works, but not the hard mouse keys

I installed Zorin on my laptop recently and it runs fine except for the issue stated in the title and it's a massive inconvenience as I prefer using these. It's not a hardware issue as they work in the BIOS and worked on Windows.

My laptop is a Dell Inspiron 5482

Have you first looked at Zorin>Settings>Touchpad and Mouse

Is it a wired USB or wireless Bluetooth mouse?
What make model of mouse?

It's the mouse built into the laptop, and sadly none of the settings help in this case.

So you are actually talking about the laptop's Touchpad, not a mouse.
If you can determine the maker of the Touchpad e.g. synaptics, then maybe something in this thread could help you:

I do, still nothing.

Just to be clear, by "hard mouse keys", do you mean items 2 and 3 in the picture?

I see this is a 2-in-1 laptop that can be set as "tablet mode" or "laptop mode".

I wonder if is somehow set, or partially set to "tablet mode". ref:

Can you look in BIOS for any touchpad settings.

Yes, it is items 2 and 3, and I checked and it's definitely in laptop mode. As for the BIOS, the version I have doesn't have anything relating to touchpad, but this is an old version and I am currently having a separate issue with running the bios updater exe from windows 11 installation media command line (says it's not compatible even though it should be) and unfortunately I haven't been able to find any solution for this.

Sorry, I can't think of anything more to help you right now.