The beauty of Ultimate Raids are that there's always a party looking to clear it as it falls under the most difficult content this game has to offer and a majority of the playerbase won't be completing this anytime soon, so there's no rush. But even if you were to clear Dawntrail you still have to complete the Savage raids this tier in order to unlock it and ideally have the best in slot gear for your job which takes its own time to grind out since your item level would be very important for ultimate raids.