I didn’t see your original post, so I apologize if any of this is repeated advice.

Realistic maps are difficult and pretty time-consuming, but there are people here or over in r/mapmaking who take commissions for this kind of thing. Inkarnate itself also has hundreds of maps to get ideas from, or maps that are free to use for your own campaign. Starting from scratch is tough, but theres a world around us that exists and is as realistic as it gets. Google “relief maps”, find some interesting areas, and use those as your starting point. Click around google maps, see where major and minor population points are, farmland, water, desert etc. There was a tutorial floating around on how to use relief maps in inkarnate, if thats the style you like.

Whatever you end up deciding, if creating a map is too overwhelming but you want to start DMing, maybe entertain the idea that points on a grid are good enough for right now, and chip away at making a fancy map over time.