When considering a theme, make sure to find answers to the following questions:
- Are the sidebars flexible? Can I choose how many sidebars I want to display?
- Is it widget-ready?
- Does it support custom menus?
- Does it work with the new WordPress block editor that got introduced in WordPress 5.0?
- Is the theme complex or simple? Which do I prefer?
- Does it support the Customizer panel? Or does it offer a Theme Settings page where I can customize the layout, category display, home page, and other options?
At this point in WordPress' development, I recommend rejecting any theme that does not support widgets, custom menus, does not deliver good customization features, or doesn't seem to work well with the new WordPress block editor. The idea behind all of this is that, these days, a situation where you can use a theme right out of the box rarely happens, so having at least a couple of customization possibilities goes a very long way.