do you know how to use daz studio? you can make some great stuff on there pretty easily.
I've been doing daz for about a year now, and I'm sure you can do something great!
So DAZ is a valid option, but it is also a resource hog and has problems with not having preset animations and poses for the sexual stuff (you can buy said resources from modding sites, but otherwise you will need to pose and animate it yourself.) It also has the same backgrounds, base characters and props as a lot of other games here. That said, it is better then the current art.
Another option would be any Illusion Studio asset pack, say Honey Select 2 for character art. While it also has the drawback of being overdone, it has preset poses and an active community releasing mods that add functions like making trap characters, adding new locations and a wide variety of genital configurations (DAZ has those to, and they do blend better with the bodies)
The third option is of-course working on improving your current art, which surprisingly isn't as bad as some may make it seem (there are way worse art atrocities committed with other games, so don't let it discourage you.) One option is to see if you can find someone willing to draft you some improved images of your current MC in order to get some inspiration with what you can do with the MC in future builds. Then its just up to you to learn how to improve your own creations.
Now im terrible at drawing myself, but the internet is full of tutorials and help guides for improving your skills at drawing. Check some content creators on youtube for example.
Lastly, the English grammar is always a pet peeve of folk here, but that too can be improved just through practice. The easiest but not cheapest (depending on if they want payment or not) way is to get some test readers to check your game prior to releases. They can suggest ways to improve lines of text for grammar and clarity and catch spelling mistakes that commonly slip by us non-English native speakers.
So that was a long post, but i guess the most important thing here is to have fun with making your game, and good luck. Don't let the comments and criticism pull you down.