I'm an iPhone user, I have a lot of apps on it, I receive a lot of notifications and I get no promotional notifications. I hope the "almost entirely useless" line was hyperbole :)
Ah, I don't use Lyft. In my city in addition to Uber we've got Bolt (Estonian, ex Taxify), Yandex Taxi (russian) and Clever Taxi (something local).
If you have the possibility ditch them, because promotional crap in the context of a payed service, with no way to easily turn it off, is an abuse IMO.