Karl Jan Clinckspoor has built a web-based utility that allows you to craft a customized executable for Ultima Underworld 2, one on which you can apply your own mix of cheats and quality-of-life improvements to tune the experience of the game to your liking:

This [tool] allows you to apply certain patches to the original game and make it easier, e.g. less EXP to level up, more health, etc. First, load the file and its SHA256 hash will be calculated. If it’s the expected value, select the patches you want to apply, then click the Apply button at the bottom of this page. Place the modified executable in your folder and run the game. Your browser might complain that the file isn’t trusted, but you’ll need to allow it. Use a tool like ImHex or HxD to compare the original and the patched file and you’ll see only a few select bytes have been changed, verifying the program is safe to use.

Now, if uploading the UW2.EXE file from your GOG-supplied installation of Ultima Underworld 2 is the sort of thing that seems at all dodgy or insecure to you, the good Mr. Clinckspoor has provided a write-up of how you can apply the same cheats to the game on your own. Doing so will require the use of a hex editor, it should be noted.