The imagery you already have for the start screen looks alright. I think you might be underestimating your own ability. The images may be AI generated, but a huge part of design is knowing how to put elements together on a page. On saying that, the "Carson Hotel" logo is hard to read, so I wouldn't place them on top of each other like that.
I work as a graphic designer and I'm actually learning game design as well at the moment.
Unfortunately, I don't have the time to work with you on this project, as I'll be tied up for the next year with course work, but wanted to chime in to say that I like the imagery that you have.
I hope you find someone that can stay true to the look and feel of your game, and add some polish, because as it looks right now, I would probably buy it.