Your laptop uses Type-C charging port, and it is made after 2016. Therefore it must use only PD (Power Delivery) as a standard means for voltage/power negotiation, per specifications for Type-C connector. I assume that Dell is a USB-IF certified computer, so the PD is the only acceptable protocol, and the communication must use CC pins.
If your "a charger" has only Type-A receptacle, it can't have PD since there is no CC pins in Type-A port. Therefore the laptop won't be able to negotiate fast charge, and likely refuse to take the default 5V level.
Now, if you will try to experiment with various Type-C to Type-A adapters, be careful not to plug Type-C to Type-A receptacle adapter, aka "OTG adapter". It will turn the laptop into host function, and the laptop will OUTPUT +5V on VBUS. If you will try some combination of cables and manage to connect it to your charger anyway, there will be conflict of power supplies, with unpredictable outcome. Don't do this.
The only chance your laptop will charge itself is if you have a charger with Type-C non-detachable cable plug. People reported that 30W PD chargers do work with XPS 13 9370, but issue a software warning that power supply is suboptimal for full performance.