Yes, the 100W USB-C PD Wall Charger is safe for phones and their batteries. A higher wattage rating does not force more power into your device.

The charger uses USB-C Power Delivery (PD) to negotiate with whatever you plug in, and it only sends the amount of power that device is designed to accept. A phone that tops out at around 27W will only ever pull about 27W, even though the charger can supply up to 100W. It will not overcharge or harm your battery.