You can't use the wrong model.
Apple xr supports fast charging. iphone8 and above models support fast charge 1 charger PD MFI certification 2USB-C to Lightning fast charge data cable The original data cable is USB-A to Lightning, which is not supported.
It may be that you do not turn on the fast charge function of the phone, you can turn it on in the Settings. Specific operations are as follows:
1, open the phone --【 Settings 】
2, click --【 Battery 】
3. Turn on [Dual engine flash charge]