I mean several monsters in Witcher have sweeping attacks; this is not a new concept. For example, this is a codex entry Ciri would've read:
Scared of these endregas, are you? Just wait till you see the warriors.– Klaus Altman, forester
Endless waves of endrega workers are enough to overcome most attackers, but when confronting more dangerous foes, endrega colonies unleash their larger, stronger members – the so-called warriors. This caste lives only to fight, and gets ample opportunity to do so while defending the colony's borders or conquering new territory. An endrega warrior's main weapon is its long tail, which is tipped with a club-like growth and spiked with venomous quils. Powerful abdominal muscles allow it to swing this tail with enough force to kill most lesser opponents in one blow.Endrega warriors also use their mass and strength as a weapon by charging their opponents in an attempted to knock them over. As invertebrates with sectioned carapaces, endrega warriors do not bleed profusely, yet recoil in great pain when hit with a blade coated in insectoid oil.
Ciri doesn't need to be a genius to figure out that she should avoid the claws and tails of a dragon, or the sweeping attacks of a cyclops or fiend. Witchers can dodge attacks from dragons, and with Ciri's teleportation it would be child play.
Ciri will likely retreat at first to study the dragon and make a fight plan as well.
As for the roar, various monsters in Witcher have a stunning roar attack, such as alghouls, dragonids (
including the basilisk Ciri killed, and a cockatrices even became known as "The Shrieker"), griffins, banshee, siren, and various vampires. The books mentioned that dragons have a loud roar, so Ciri should be expecting it, and teleport far away to safety to recover (that is, if she gets hit by the roar in the first place).
Ciri can just take potshots; standing at a distance, then teleport-slashing Rathalos wing or back, then teleporting far away to observe an opportunity to strike again.