Totaly get you. There are some apps that let you pay for other providers, like the Shell Recharge, but the mark up is just too much.
Even the Spark Aliance merging Ionity, Fastned and 2 more companies is just letting you start a Fastned charge using for example the Ionity app. But the Fastned autocharge does not work with the Ionity subscription, etc.
The charging market is weirdly lagging and feels like EV 10 years ago.
It does not help that my city in the Netherlands chooses a new charge point operator every years or so. So for AC charging prices range from 33 euro cents to 89 euro cents plus start fee plus per hour fees from 0 minutes. And on top of that latest example from my street, Shell Recharge is even higher markup, for an AC charger.
There are the attempts to have all new chargers support payment cards, but the companies take advantage of it by allowing you to pay with a credit card the normal price but if you use their app, it is cheaper.
My guess is this is not gonna improve any time soon, so i just made a dedicated folder of apps on my phone.
Curious to see what others feel like.
Not got one single charging app. (Thank god) and intend to keep it that way. 
