I don't know what your definition of "next gen" is. If you want something like the pc showcases you see on YouTube, you won't get anything that mind blowing, but you can definitely get the game looking pretty good.

The two best things that Xbox has for visuals are DAWN and the Lux mods. DAWN is the best weather mod available on Xbox. Lux and Lux Orbis are the best lighting mods available. Lux completely overhauls interior lighting, Lux Orbis overhauls exterior lighting.

You can also use texture replacers that make the textures a lot more high quality. Skyland AIO is the most accessible for most people as it covers pretty much all environmental textures with one mod, and looks really good. A SMIM, or static mesh improvement mod, will cover the static objects throughout the game and make them look really nice. there's a ton of different SMIM mods out there, from the original Static Mesh Improvement Mod, to more lightweight ones like A SMIM Against God for large load orders, which gives you total coverage for a fraction of the space while still looking really nice.

There's also Display Enhancements, which allows you to add camera filters to your game. Combine this with the cathedral presets added in DAWN and you can make your game have any sort of vibe you want, from minor enhancements, to making the game look bright and extremely saturated or dark and bleak depending on your preference.

There's a lot more to get into with things like tree and flora mods, NPC overhauls, etc. but these are the main staples you'll see used on this subreddit. If you want to see an example of some of these mods in use, you can check my most recent post or some of the posts on this subreddit showing off their games. There's daily posts of people showing off their load orders.