Your electric vehicle (EV) determines the power at which it can be charged. If your EV supports a maximum power of 70 kW, it won’t matter if you charge it on a 150 kW or 350 kW charging station, you will still only get 70 kW.
IONITY already deploys chargers that are capable to deliver 350 kW of power. Most currently available EVs aren’t yet able to charge at this level of power. Many car manufacturers announced electric vehicles that will come in the near future which can take advantage of the high power chargers.