I'm inclined to say yes, but it depends on the circumstances that lead to Biden's resignation. As a non incumbent, I think she'd be favored only against Trump. Against any other Republican nominee, unless said nominee is someone like MTG, I think the GOP would be favored.
What makes you believe she'd be favored against Trump and not other GOPers? I don't like to say it, but Trump is certainly still one of the strongest GOP candidates because of his loyal following. He has twice exceeded expectations by a significant margin. DeSantis or someone else could be a formidable opponent, but only under certain circumstances. At least I haven't seen a compelling argument why he (or any GOPer) is so much stronger than Trump. Other GOP candidates may win back a smaller share of Romney voters, but a ton of Trump voters only vote R because of him and not out of any party loyalty.