It looks like Sonic Frontiers will have DLC, based on this promo

Sega selling add-on content isn't too surprising, but we may have our first soft confirmation of Sonic Frontiers DLC.

Looks like Sonic Frontiers isn't over and will release Free DLC's on 2023 : r/gaming

Sonic Frontiers' Final Horizon Launches Today With New Trailer and Screenshots - Games - Sonic Stadium

Sonic Frontiers Free DLC Roadmap Reveals Tons of New Content Coming in 2023

Sonic Frontiers

Sonic Frontiers' Free DLC Roadmap Includes New Playable Characters And Story Content

Sonic Frontiers Official Website

It looks like Sonic Frontiers will have DLC, based on this promo

Fans are calling Sonic Frontiers' DLC 'the hardest gameplay in any Sonic game

Sonic Central 2023: Celebrate Sonic's Birthday With New Releases and Updates - Xbox Wire

Sonic Frontiers Is Getting 'Multiple' Free DLC Content Updates Over the Coming Months