Out of the box the mouse sensitivity on my system is incredibly high, is there a way to fix or adjust this?

Sure! There should be a few options you can poke at with a stick in the dosbox configuration file in the install directory of the game.

While you're down there, consider switching to DosBox Staging and adjusting the graphical optiojs to take full advantage of the lovely new video modes.

I had the same issue and just now solved it.

In GOG Galaxy when you have Ablion selected next to the play button there is a settings button. Press that and at the top you should have Additional executables, and in there Graphic Mode Setup.

If you select Graphic Mode Setup you can change the mouse sensitivity in the Advanced Settings section. I set mine to 25. I tried 1 but it was far too slow haha.

Not sure what all the graphic mode settings do in basic settings!