Valve have now rated Sonic Racing: CrossWorlds as Steam Deck Verified ahead of release, but we also now know you need to always be online to play it.
Yep, even for single-player racing you'll need an internet connection which is not just for Steam Deck - all platforms and it's also shipping with Denuvo Anti-tamper. The Steam Deck rating came in early this morning, with Valve testing it against the latest Proton 10 Beta. Since it's Verified for Steam Deck it's also SteamOS Compatible, and will work on other Linux systems.
Forcing internet connections doesn't exactly make it very portable. A shame to see more games doing this.
Check out the original trailer below:

Direct Link
And the most recent trailer below:

Direct Link
From the Steam page:
Race across land, sea, air, and space in Sonic Racing: CrossWorlds! Warp through Travel Rings into new dimensions where something new awaits around every twist and turn.
Speed to victory solo or as a team in a variety of offline and online modes and compete against players from around the world. Build the ultimate vehicle to match your racing style, unlock gadgets to gain the upper hand, and unleash power-up items to bring home the win!
Ready, Set, Warp!
Race across 24 tracks and warp to 15 CrossWorlds with Travel Rings, a unique gameplay mechanic that transports the iconic characters from the Sonic and SEGA universes into new dimensions. Use unpredictability to your advantage as you change the landscape of each race!
Race With the Best!
Choose from 23 iconic Sonic characters, the largest roster of any Sonic racing game!
Make It Yours
Mix and match between 45 unique original vehicles and 70 different gadgets to trick out your ride, level up your kart, and create the ultimate machine to match your racing style.
Gain the Advantage with Powerful Items!
Dominate your opponents with 23 different items including returning favorites and all-new items like the Monster Truck!
Multiple Ways to Play
Gather with friends and play local split-screen in Grand Prix and the new party mode Race Park, compete against a community of players from around the world with up to 12 players online in World Match, or test your driving skills in Time Trials.
The pre-order price is £64.99 on Steam but Fanatical do have it with a 13% discount right now.

Wouldn't be surprised if we get an offline patch within launch week.
Still absolutely ridiculous but at least SEGA incompetence might come to the rescue.