Cascadia am/fm and sxm

OK y’all

new driver here just out of school.

company put me in a new cascadia and the am/fm antenna is non existent and radio struggles to find a station. the SiriusXM cuts in and out horribly

replacing the am/fm ain’t really a hard thing for me but I’m not sure about the SiriusXM antenna

my thoughts are to get a mirror mount antenna and mount to the truck and run it into the radio. My only question is do they make an adapter that will plug into the tuner of the radio for the SiriusXM and allow me to plug-in an aftermarket SiriusXM antenna. Company I work for shows a little concerned for replacing the factory Sirius XM antenna to fix the reception issue