Activating apple pay with assistive touch, Power button is broken.

My mother's iPhone 10xr recently had the screen cracked , after taking it to get it replaced at a local store the power button ceased working (the technician almost certainly ripped the cable during the replacement, the phone was fully functional aside from the display damage), regardless of getting the button replaced, is there any way I can enable apple pay with assistive touch for her, I see there is an option to enable that function in settings but It needs a double Click of the broken button to enable?, or is there a way I can remap one of the volume buttons as a power button?