They were careful to word it as "take home pay guarantee". That guarantee looks at the actual payment per delivery, plus tips, and makes it up to a minimum.
It seems clear from all the marketing materials I've seen.
Doordash can simply argue this guarantee was on top of the regular pay, and was totally optional, and every contractor only stands to gain from this guarantee.
I'm pretty sure the whole aim of this case is to crucify doordash in the court of public opinion, despite their case being strong in an actual court of law. My elected politicians shouldn't be allowing that - if there are gaps in the law, address them directly!