Iphone 12 pro max won't update without wifi

Phone automatically turned off when charging then it said temporarily restoring data then it showed that I didn't have any service. It also couldn't connect to wifi to update the phone so now I cant even use the phone at all and now its telling me to connect to Mac or to a PC that has iTunes but, now I think with apple up to date it doesn't even support iTunes anymore lol someone please help.Thanks.