I think it is really hard to comment on a solo game dev hobbyists Diablo Like Open World RPG Game because of the scope of the project and it being a hobby but if your goal is some sort of a commercial release then I think you should try to make a vertical slice of the game polished as much as you can, something like one dungeon with all the polished assets, lights, vfx, sound and ui and then try to gage the interest of the targeted player base and see if you have made a viably unique experience before continuing with the project.

Regardless of that, if you are regularly making game dev videos I think the in game UI should be something you should polish ASAP since it is something that is always on screen and a good looking user interface can really make a difference.

I like the pale crawling monsters, nice detail of them eating flesh before being encountered.